Common sense should apply here, I've bought 77 rif's second hand from here with relitively few issues (as above), admittedly most are wall hangers but they all work apart from a few boneyards that I knew had issues, I have 5 rifs in my collection that I've listed as faulty but I'm pretty sure they were all sold as boneyard, the ones I fixed were sold as working( I think). I have a couple that I remember thinking they were metal bodied & they turned out to be 'sportline' but the only rif I regret buying was brand new & not to scale so it's never seen the light of day (we don't talk about the blue one's).
If in doubt... don't buy,
if disapointed or feel scammed there's always the paypal claim process (honest sellers have nothing to fear).
On a possitive note, I'll have more weekends off soon and have already started preparing myself & collection for potential game days, even second hand purchases from the classifieds.