I found a Rem. rolling block rifle in a pawn shop of a friend of mine today. It looks like the ones on the net that are called Mexican, judging by the rear sight. It has a breech block just like a No1 ,thumb lever turnde up, but has large barrel shank like a No5. I didn't look to see what size firing pin it had. It looks like cal. is 7mm. I think the last pat. date is 1874 My question is , is this a late no1 or an early no5. Any help would be appreciated.