It's common practice to have a gun tightened, barrels re-blacked or browned.
The furniture and pins could be blacked or blued at the same time
A clean out of the checkering and a bit of oil on the woodwork will improve the looks too
Without the full hit and expense of new springs and internal parts, this kind of work will go a long way towards keeping a good old gun in tip top condition.

Sadly, some are past the point of no return mechanically and economically.

Rust never sleeps !