Does it have a dolls head rib extension too?
Sounds like you have one of those DS guns that are DS in name only. There are a good amount of them out there. You basically have an H grade that is marked as a DS. Having mismatched grade stamps on barrels and frame are not out of the ordinary on Lefever guns.
I have to disagree with a couple things here. These DS Grade Lefevers that have the characteristics of an H Grade with Twist barrels are not all that common. I have a couple of them, but would estimate that less than one out of 25 DS Grade Guns are in this configuration. Probably much less. And I have never seen one of these with ejectors, so that is interesting. I've also never seen one in anything other than 12 gauge... yet.
The mismatched numbers on the frame and barrel are definitely out of the ordinary if no numbers on the barrels match those on the frame. There are a number of Lefever guns that have more than one serial number on the barrels. But this seems to indicate that the gun had been returned to the factory for major repairs such as a replacement barrel or upgrade to automatic ejectors. This practice consumed several thousand serial numbers, but normally, one of the numbers will match the number on the frame and forend iron. But If no serial numbers match, I'd suspect that the barrels are replacements, and not original to the gun. The only exception to this might be found on a very late gun that was assembled by Ithaca from left-over parts. But none of these unusual DS guns with H characteristics seem to have the features associated with Ithaca assembly.
