Yes, there are a lot of good sportsmen here that are willing to help out.
If you still bird hunt, small game, or shoot shotshells from the gun, I'd say not to shoot slugs from a full choke. What I read says not necessarily damage to the gun but accuracy suffers.
I was given a Mossberg 185 20 ga as a boy in the 60's. I hunted small game and shot at a deer with it. I soon graduated to an 870, and then a 94 Winchester, so the little Mossberg sat in the closet. Years of disuse, then it went through a house fire in the 70's, and it was looking grim. I cleaned the gun after the fire as best I could, Gunslicked the bolt and trigger, and it sat another 25 years. One day I decided to put it back in commission (I hunt a barrier island that does not allow centerfire rifles) as a dedicated slug gun.
I started reading about chokes, and all articles talked about a 3-inch +/- forcing cone. I measured 3-1/2" from the muzzle, strapped it in the bandsaw & cut it, then lightly dressed the crown with an automotive valve-grinding stone in a hand drill (slow!).
I then took a set of fiber-optic sights for an inline muzzleloader and JB-welded them to the muzzle and the breech. The last task was to make a cheekpiece so I could actually see both sights. It's ugly but it's mine.
A can of flat black, brown, and green camo'ed it perfectly and it was ready to hunt. With the choke gone and the green & yellow Remington rifled slugs, it is a 60-70 yard gun. (If your eyes are still good enough to use open sights!) I'm 61 so the deer has to be close. I mostly use a scoped H&R 20 but once in a while will break this one out.
The best part about hunting with it? We get LOTS of PA/NJ guys down here hunting the beach. Most of them are at least average or better in the way of income, and tote some heavy-duty ($$$) firepower. Wait till they see an old white-haired swamp rat carrying a yard-sale derelict by the barrel over his shoulder. They're polite but are still funny to hear the questions and comments.
Anyhow, a couple of afternoons, some JB weld, a pair of hi-viz muzzleloader sights, and presto! If you have a young teen or lady that can't carry a 8-1/2 or 9 lb slug gun, give them this. With the green&yellow Rems the recoil isn't terrible and they will learn woodsmanship. (Get the deer in close.)