Oh you can make anything work. (almost) The question is will it work correctly & give you a sound stock. Since you have minimal depth it would be unlikely the plank will work unless it is a very straight stocked Lancaster.
Lay a pattern or another long rifle on the plank & mark it & then look at the grain thru the wrist & lock, that is the key points. If it is not correct there I would not waste my time on it. I would refrain from stocking a rifle knowing the wood was not right in the first place.
I have lots of walnut, cherry, maple that is beautiful wood but all it is, beautiful wood, it is not gunstock wood. Then I have some that is wonderful for gunstocks & I would not consider it for furniture.
:imo: