There is nothing complicated about 95% of springers, and that includes the simple Osprey.

Naturally mechanical aptitude is always required, and even more naturally we have no idea of yours

But removing the action from the stock is simplicity itself, remove the forward stock screw on the underside of the stock fore-end and the retention screw that also secures the trigger guard, the one at the front. The stock then just comes off.

Re-bluing (blacking) is not generally a DIY affair if you may not be up to taking the gun apart some bluers will do this for you. try contacting RichardH on here and ask, if you wish to take this further.

BTW, it means re-finishing the metalwork to as-new condition if the rust is not that deep that it can't be polished out. If it cant be at least the pitting will be blued so barely visible.

The stock is best lightly sanded till all old varnish is removed (or use Nitromors, with care) and the dents are steamed out. Then refinish with rattle-can coloured lacquer (varnish).