I can not read the numbers that are close to the action, but the last two numbers appear to be "08". Some of the proof houses in Europe would stamp the guns so that the first numbers were the order of guns in that year and the last two are the year. So, this gun could have been built and proofed between 1901 and 1909. I can not see the other proof marks that well on my lap top. I think the first large number is the serial number. What is at the end of 2772? I can not read those marking either. The use of the underlug pin to hold the forearm in place is very common on the European guns of around the turn of the century, being a hold over of the muzzle loading days. Gun is probably around 120 years old and some other people may be able to read your proof marks and know what country of origin for the gun. My gut says its British but that is a guess.