Does finishing a laminated stock improve its resistance to warping over years' of use in damp climates, such as Washington and Oregon west of the Cascade Mountains? I guess another way of putting it is does omitting the finishing do anything other than make the stock aesthetically unappealing?

That might just depend on the particular finish one is applying or omitting.

Laminated stock because of the thin layers of wood glued together, are less likely to warp in humid and wet conditions. But I would still apply some kind of finish. Poly will seal well, tung oil with hardener or tru-oil will help seal the wood also.

I thought all Boyd's stocks came with a poly finish unless ordered without a finish.

First rifle I ever re-finished was a old laminate and I treated it like it was a fine walnut. I have to laugh about that.

In more recent years I wondered if oil is the last thing you want on laminate given the use of glue within the stock.

Now I would probably give it a good cleaning and just use paste wax.

Thoughts on that?

I've used Gun Sav'r Pro Custom Oil from Brownell's on some of my Boyd's with no problems at all. It holds up well and looks great. https://www.brownells.com/tools-cleaning/gun-tools/stock-finishing/pro-custom-oil-gunstock-finish/

I've used poly coating that I pick up at our local Bi Mart stores, and/or a stain if I desire it on the Boyd's Stock.

I've finished about 15 to 20 of them for myself, and did others for friends and a few folks on the campfire.

I live in SW Oregon in the Rogue Valley. All of my rifle stocks, that are from Boyds have 15 to 20 years on them.
They have held up without requiring a refinish ever.. and they've been out in all sorts of bad weather. Most of them have been on Ruger 77 Mk2 Stainless actions and barrels.

They have resisted wear and tear from bad weather conditions, and field hunting in the mountains around here as well as the rifles I have, that have Hogue Rubber stocks on them... but the Boyd's Laminates are much more visually appealing.

Hope this helps ya out.

Cheers,
seafire