Boy, how did our grandfathers ever kill anything with all of those wood stocked, blued steel rifles rusting to powder in just one hunt?
In other words, no you don't need stainless. If it gets wet just wipe it down.
If it had not been for a great deal on a stainless steel 338RUM I wouldn't have a stainless rifle. All of my rifles would be wood stocked, blued steel.