Precisely dating a martin guitar
1995 -- PRS changed the tremolo system dramatically.The saddles are no longer highly polished and they tend to dull up and tarnish.A small company can go and handpick their wood but a large company has to literally buy wood by the ton and hope for the best.1998 -- PRS introduced their new low mass tuners...CNC manufacturing techniques allows PRS to build more guitars than ever but a lot of the original soul of the guitar is lacking.Also when you produce huge amounts of guitars there are other problems with wood for example.1991 -- PRS stopped offering real abalone shell as the inlay material on the fingerboard.They went to a high quality, less expensive, but real mother of pearl.
the newer one that is a 2 piece bolted together unit. This affects the playability of the guitar adversely and also reduces the value of the guitar greatly. This cost cutting move was especially dastardly, because it's impossible to visually tell the difference: The wood is painted opaque on most of the models.
1993 -- PRS came out with their version of a one piece stop tailpiece.
This tailpiece is made from white metal with absolutely NO saddle adjustment (not recommended.) The ones used previously were the excellent quality Gibson style Nashville 2 piece system with fully adjustable saddles.
I really hate the new PRS Stop Tail Piece 1995 -- PRS stopped using the mother of pearl inlay in favor of an artificial laminate known as Abalam.
Still, you have to remember Gibson uses Mother of Toilet Seat, which is nothing more than plastic.