Verify through the records that it left the factory looking like what you see now. Originality seems important to you, and it should be in this class.
No use in going any further or wondering about anything else if it isn't.
The 'Chambers 3 Inches' stamping and chamber ream is a simple after market upgrade done to 2 3/4" guns to increase the value.

Start at the beginning, get all the specs to check originality, then go from there.
This in no way is a reflection on the current owner.