Belgian T-Bolt -- stock finish

Rifle in question is a Belgian made T-Bolt, with s/n 57###X71. So it is apparently 1967 production. I know it was a salt wood gun, I recall seeing it with salt crystals all over the receiver when--after years in a case--the salt issue was discovered. I know it was sent to a gunsmith for repairs. I don't know if they did work on premises, or if it went back to Browning. That information is lost, so I don't know any details of what was done to repair it. But I was told the damage had been taken care of. So my assumption is the stock was replaced.

The stock looks like it really needs some oil or something to protect it, it has some wear and a dry appearance to it. I am no expert in woods or rifle stocks, but I guess this is walnut. The butt plate says "Browning" on it, which makes me think it's not an aftermarket stock. Not sure if the butt plate is plastic or rubber, but it has some funny bubbling (not sure what to call it) going on around the edges (i.e., on the side-facing surface at the edge, not so much on the rear-facing surface).

What product (if any) would you apply to the stock to protect it and improve its appearance?

Thanks for any advice you can share.