You are getting much better information here. That one appears to be in very very good condition. It is common for the barrel latch to have a little play. I wouldn't do a thing to it other than wipe it down with a soft oiled cloth. It looks to be a 3 1/2" barrel, there were just a couple hundred made with 4" barrel.
These are a 4", 3 1/2", and a Second Issue, along with a couple 1 1/2 Center Fire top breaks.
