My LOTR has the ribbing. Bought a NOS LOTR playfield to clearcoat it because we love the game and it will probably never leave. It also had the ribbing. Scuffed the factory clear, added 3 coats of clear, sanded it flat, then added 3 more coats of clear. It's been curing for about 4 months...
Hate to give the OP sad news, but even our newer games have the ribbing. But no worries, the dimpling that's coming will flatten all the ridges you see.
Just play it and have fun. It doesn't look like ANY games by ANY manufacturer are losing value these days, with any flaws they may or may not have.