The four "national crew net" frequencies are all narrow band. 163.1000 and 168.3500 are both wide area common federal government itinerant frequencies, I don't remember exactly what the NTIA Redbook calls them, but that is pretty close. The four crew net frequencies have the same terminology, but it is the narrow band frequencies that are actually given the name "crew net" by NIFC.
Disregard the above. I misunderstood the frequencies being discussed. My brain must have been in another country at the time. I'm going to provide information here regarding the use of the 163 and 168 frequencies ScannerDude244 found in the Pinnacles handheld.
What f40ph posted is correct. There are two additional national crew net frequencies for a total of four frequencies. They are actually called the"National Intra-Crew Plan" frequencies.
National Crew 163.7125
Primary Crew 167.1375
Secondary Crew 168.6125
Tertiary Crew 173.6250.
This assignment is not an exclusive one as any federal agency can use these four frequencies for any purpose, anywhere and at any time. Interference is less likely because of the lower power used, use of CTCSS/NAC, NIFC-Interior-USFS use being mostly in rural areas and the number of federal agencies whose radio use is quite minimal. There is a 30 watt limit for mobiles and bases, but these are primarily used in handhelds.
National Crew is used for crew mobilization at their home unit and as a travel net. It is not to be used at the scene of incidents. The remainder are for use at incident scenes. It should be noted that these frequencies are not to be used for tactical purposes, but for coordination within a crew. Coordination is essentially crew logistics. For example you might hear: "when you bring up the two chains, bring up a full dolmar (fuel mix and bar oil container) and three saw files and if you have room, a Cliff Bar for everyone," or "we figured out how to get the buggies (crew transports) closer to the line, there's a two track (non-constructed road) that takes off to the left after you pass the other drop point, take it to the end and wait for us." Remember that "intra crew" means within a crew. Communications between crews are to be conducted on the assigned tactical frequencies. Crews were advised to chose one of the three on scene frequencies with the least interference and use either CTCSS tone guard or switch to digital and use a NAC to eliminate having to listen to other crews.
Prior to the assignment of these four frequencies in 2005, many crews were purchasing FRS/GMRS radios for communications within a crew. This is not permitted by agency policies. This is why the national intra-crew plan was developed. In spite of this some FRS/GMRS radio use continued. To reduce, possibly eliminate this NIFC has been given permission for the use of the military "Intra-Squad Radio" (ISR) set of frequencies. These frequencies are in the 380-390 MHz range so separate radios have to be used. These and all the NIFC assigned frequencies for incident communications are listed on the Wiki page I maintain. The page is a comprehensive list of all the known frequencies used on large (managed by a national Type I or II incident management team) incidents. The page can be found here:
National Incident Radio Support Cache - The RadioReference Wiki
ScannerDude244 and others, the 163 and 168 frequencies you found in the Pinnacles NP radio are listed in the database. Bring up the database main page, look for the tab "Nationwide Frequencies" above the map. Click on it and scroll down to the "Federal" heading and at the bottom of that list you will find a link for the "National Incident Radio Support Cache." That page has some errors, omissions and non current issues. Clicking on the "Wiki" tab on that page brings up the same page I provided the link to above. I've not had the time to make the submissions to update the database page yet.
In 2005, directives were issued for the federal government's narrowband conversion in the NTIA (National Telecommunications and Information Administration) "Redbook." 163.1000 and 168.3500, which had been federal government wide common itinerant frequencies were to be used for temporary portable repeaters, with 168.350 being the input frequency. They were no longer to be used as simplex commons. The four "Intra Crew" frequencies l listed above were to replace these older federal common frequencies (168.3500 and 163.1000) for simplex use. 168.350 was widely used in national parks for tactical purposes and 163.1000 was used in a limited number of parks for the same purpose. After 2005 federal agencies, most especially the National Park Service, started to replace the older commons with 168.6125 (vice 168.3500) and 163.7125 (vice 163.1000). That is why ScannerDude244 found them in the Pinnacles NP handheld he examined.
In practice the feds have not stopped using the older common frequencies for simplex use. In fact, 168.3500 with a 123.0 CTCSS has been assigned nationally as the smokejumper tactical frequency. Post 2005, I've heard a 163.1000/168.3500 repeater nearly every time I've visited the L.A. area, so the temporary conditional repeater use directive is not being followed all the time either.
I know that this post is off the topic of what radios the NPS uses. I hope this helps explain the use of the frequencies found in the Pinnacles radios and then some.