Wayne if your mounts look like they did 30 years ago then they must have looked bad when they were first mounted ;D Skin mounts age and unless you kept them in a vacume, in the dark then they have deteriated. You probably havent noticed because you see them every day. If you post some good pictures of your mounts I bet I can find many flaws with them.
Keep in mind I am/was a taxidermist. When you get a skin mount, you skin a fish and then glue the skin to a foam body. You have to position it correctly. You also have to position the fins and the jaws and fill in gaps with filler and many other steps in an attempt to make that skin into a fish. The reality is by the time you get "your" fish back it is not the "same" fish you brought in. Unless the Taxidermist is extremely good your fish will be off a little in girth or length and many many skin mounts are not posed in natural positions. After the fish is mounted and dried it is then painted. My point...........It is not exactly the same fish as when you brought it to the taxidermist. Now keep in mind, you now have a rotting cracking yellowing warping fish on your wall. Sure it doesn't happen overnight but it is happening.
People argue that they want a skin mount because it's their fish, I disagree. It's the skin that somebody attempted to put back together into your fish.
Now I'll discus replicas. First off they are molded from a real bass in a natural pose. The mouths are positioned properly, the fins aren't over extended, and the body is correct and proportioned. It is a much more accurate representation of a real bass then a skin mount. A replica only requires dusting, as it is not rotting. It does not yellow. It does not distort. It does not become dry and brittle of have the scales lift or fall out. It is a superior product in every possible way. Many of the top Taxidermist in the country wont do a skin mount because they are so inferior.
It is my "professional" opinion that a replica is a better and more accurate depiction of "your" fish than a "real" skin mount.
So Replicas ARE the way to go with any of your trophy fish that you want mounted.