The Smith 627's pretty much rule ICORE. They are 8 shot guns. A stock one with iron sights is a limited gun. You could shoot the same gun with dot (Cmore, OKO, Aimpoint.....) that puts you in open.
Now if you shoot a 6 shot gun that puts you in a different catagory of limited but still limited.
This is the quick version.
The even more simple answer is buy a 8 shot Smith 627 some hearthco moon clips, holster, belt and North Mountian moon clip holder and you will be set up to shoot limited.