I agree with Mike Brooks and Allen Martin on no butt plates. Of all the original rifles I've restored over the years it was the ones with butt plates that had the damage. Many had broken toes because of the lower screw in the butt plate and toe plate screws, all working together to weaken that area. I don't remember a single "no butt plate gun" that ever had any real damage other than normal wear.....the same kind of wear that you would get over time on the legs of an old ladder back chair.
A crack developing in the butt to me signifies....most of the time... that the stock was not completely dry and/or completely sealed when the gun was built. I've seen the same "checks" on guns with butt plates. Come on now.....stocks are made from "wood"....
I know that today our guns constitute a major investment for all of us and most fellows tend to "baby" their guns and not really use them as men used guns 200 years ago. So it gets a ding or a little crack somewhere. So what....it's a tool. The gun still functions. I bet guys today don't take that much care of their claw hammers.
I'm currently putting parts together for a no butt plate", .50 or .54 smooth rifle in a slab-sawn piece of walnut for myself. Gonna be a plain-Jane....
I think a well-made gun with good lines that shows honest use, possibly a crack or two, even some damage and repair... is beautiful....but that's just my humble opinion.