What I mean is, if I am doing GPS location scanning, and I drive through an area where they have an LTR Passport system, and it has service types that I have selected, will my 536HP attempt to monitor the system or skip it?
As LTR systems are not in the Sentinel database, because that system type cannot be trunk tracked, then no, your 536HP would not attempt to receive it. This is similar to what happened with NXDN. NXDN systems were not in the database, until an upgrade for that format was available, and a few weeks later, Sentinel started including NXDN systems in the masterDB. I have no idea if a Passport upgrade would ever be offered. There may not be enough systems of interest to enough scanner owners to be economically feasible.
The only way to monitor it at all would be to enter as conventional frequencies in a Favorites list, and be sure to include the location details in the main RRDB if you want the GPS to control reception. While you could assign service types to the frequencies themselves, there's no way to include talkgroups, with or without a service type, so your options are limited.