This is not true. If you can identify/prove it was yours, it still belongs to you and you get it back without having to pay for it again. Salvage yards, pawn shops, etc. know that if they unknowingly receive stolen property they lose it once the owner comes along, so they are usually pretty careful about it.
The basic legal principle is that the thief can't convey rights in the stolen property to the salvage yard greater than his own rights, which in this case are none. The famous law school textbook case illustrating this is "in re Two Bose Speakers", 17 Kan.App.2d 179, which explains that with a few exceptions (such as currency), someone buying stolen property has no greater rights in the property than the thief they buy it from.
John