Honestly police trade ins generally have been used quite a bit but alot of them are well maintained. the outsides generally will have a bunch of wear for the holsters they use but like I said they are generally well maintained.
I bought my glock 23 used from vances but it was not a police trade and I inspected it and its was in great condition. usually when you get a used gun from vances alot of the accessories will be missing but thats generally not a big deal, you will at least get the necessity's