finished better? I dont know how it could be finished better..my 452 FS is of excellent quality. I dont like the idea of barrel swapping. If anything the 455's are of less quality then the old 452's. Company's will always find a cheaper way to produce products, example would be the cheap sights they put on the 455's, another example would be Glock slide finishes on gen 1 and gen 2 models, stick a gen4 glock nest to a gen1 or 2 and you will see what im talking about.
just look at a BRNO model 2 and a 452 Lux, similar rifles, but the BRNO is of better quality, and some say accuracy as well. Usually when dealing with things like firearms or tools, older production is higher quality.