Compressor filters, do they really work?

All I can tell you is here, in WV, I have used two or three small aluminum filters, each with a cotton filter first and then molecular sieve beads. When I opened up three of my rifles, there was not a trace of damage. I've posted pics on here. The small filters got too tedious to fill, so I bought a large aluminum filter that takes cartridges of cotton, charcoal and molecular sieve and now use them. I'll open my guns again this winter to take a look, but I'm guessing it'll be just fine.
Which one of those big aluminum ones did you get. I got a rovair getting delivered Thursday and it just has the little aluminum one.

Thanks
Jon