Oy. My eyes hurt.

That is an 1894 patent R model, that has undergone serious modification. It didnt come with a vent rib when it was new, and the stock is a long way from factory. It appears one sling swivel was good enough for what who ever did the modifications was after.
The condition of the metal seems good. I wouldnt spend a lot of money on changing things on the gun, that is money you wont ever see again.

I highly doubt there is an identical gun to that one out there.

Best,
Ted