I agree - its a fairly recent thing - the test fire/headspace validation.They may be now, but I'm telling you, there is no possible way two of my older ones would have functioned. Unless they dipped the whole rifle back into a vat of Cosmoline after they test fire it.
It would make sense that they are test-fired now, since so many of them are parts guns, and many of the parts are new (specifically the barrels).