Many, many guns were produced and sold with the 'makers' name marked on the action only. The absence of barrel or rib markings in no way signifies rebarrelling.
You need to post some good close-up photos of the marks on the barrel flats and also the action flats and go from there.The proof marks for Nitro generally started in 1896 and were altered in 1904.For example if your gun has barrel flat markings from 1896 or later and an action flats marking from an earlier period then it may well have been rebarrelled but I would say there is very little chance of that.
