I would assume that a "deer preserve" would have to have tagged deer, just like pheasants and other birds on a hunting preserve have to have a band identifying them as preserve birds. Doesn't necessarily mean you couldn't shoot a wild bird, or buck in this case, but are really "hunting" the tagged preserve animal. DNR could tell you for certain, I'm just expressing opinion based on what little I know about preserve hunting.
Logic says it isn't unreasonable to allow rifle hunting in such a case--a farmer can go out and shoot his cows with a rifle if he wants to, or if you're willing to pay the right amount I'd guess most farmers would let someone else, also. And not a lot of difference either, could find a farmer with a really big pasture if you wanted to be "sporting". Deer should make a nicer mount than ol' Bessy, but would get more meat from the cow.
If they're going to hunt in that manner, I'm not sure that a slug gun or pistol is enough compensation. Ought jump on their back with a bowie knife in their teeth.