Both are (not well matched) Plain Twist Bill.
And I agree very high condition.
The chambers are likely 2 1/2 or 2 5/8", but were not marked in that time frame.
The bore looks to be 18.2 mm = .7165" with R choke < .008" and likely cylinder
Left muzzle constriction is 17.5 = .689 or .0275" choke = Imp. Mod.

If the bores and wall thicknesses check out should be a fun shooter! In light of the 130 year old wood I'd suggest 7/8 oz. at 1200 fps loads, which have been commercially available from Fiocchi and others; and nominal 2 3/4" Fiocchi loads tend to run about 2 5/8".