There's some good info here:
But, yeah, you need to know with 100% certainty what frequency they are on.
If you are in the U.S.A., there are a number of FCC regulations that will make it difficult or impossible to use these. One of the reasons they are on the auctions is that they are essentially useless to all but a very narrow group of users...
If they are VHF or UHF radios, then the only place they will be legal is on the amateur radio bands. That will require you and
all other users to study for the FCC Amateur radio test, take the test and receive amateur radio licenses. It's highly unlikely these radios were used on amateur radio frequencies, so that means they'll need new channel elements and tuning. That won't be cheap or easy as the channel elements can be hard to come by.
If they are low band radios (30-50MHz), you can go through a frequency coordinator and see if you can get assigned the same frequency that is in the radios. Then you'll need to pay the FCC for a business/industrial license to use them
But, then again, these are -old- radios, and they'll no doubt be badly out of tune and it's entirely possible that capacitors have leaked and need replacement. Again, that'll be expensive and time consuming to rectify.
Hate to sound so negative, but there is a reason these radios are on the used market. You will have a hell of a time making them legal to use, and you may very well sink more money into them than if you had just purchased new radios from the get-go.