I have one of these from around 2000 or so with a silver finish. Crosman Pellgun Oil literally saved this thing (I had never knew about the fact that you had put that on CO2, so each of my CO2 guns were in dire need) when it had started to leak enough that it would only get 3 or 4 clips before being too down on psi. Mine now shoots hard and still very accurate (ran 3 CO2 cartridges with tons of Pellgun Oil on the tips and even put some in the air valve and that eliminated all leaks). Hopefully the issues you're having can be simply solved like mine were.
https://www.pyramydair.com/product/crosman-8-shot-rotary-clips-fits-t4-1088-pistols-3-pack?a=1236