I can't speak for Ahrends grips specifically, but I don't care for poly on any firearms wood. I guess I'm just old fashioned but I am a traditionalist and don't care for the "plasticy" feel or look of polyurethane finishes.

When I refinish rifle stocks I much prefer to use a hand rubbed finish real pure Tung oil. It is time consuming but I much prefer the way it makes the wood look richer and feel more like wood instead of plastic. Tung oil finishes are also much easier to touch up in the event of a mishap too.

Poly on the other hand is a cheap and and easy finish to apply and it does offer superior weather resistance.

Lots of great info about firearms wood finishes over on surplusrifleforum's "Stock Care and Replacement Stocks" forum.

Of course I tend to be old school and I will admit that it is a personal preference thing. YMMV.

In fact, I don't even know if they use pure Tung oil or just one of the varnish based finishes often marketed as "Tung Oil".