My experience in buying FSU cameras on thE bay is that when the description does not include a definite statement saying that it is CLA'd and working then I do not expect it to work perfectly as received, regardless of what the seller says. (Mint, works well etc...)
It's fun to be able to tinker a little with these and allows the purchase of cheap examples.
Over my 30 -40 purchases I have never really been stung (apart from "works perfectly at all speeds"....which turned out to have no slow speed mechanism fitted).
A few have worked from the box and one or two from a Ukrainian seller have been as good or better than described.
It's worth realising that a good test of any camera is time consuming and may not even be complete without a proper film test anyway. Your average camera seller will not have invested this time before selling.
My advice is to buy carefully and cheap. Get one or two to learn a few tinkering skills on. Ask here for advice if needed.
I think one of our members here once wrote that any FSU owner/user should expect to have the hood up now and then....and enjoy them..