Very nice - You have a First Model Colt London Navy.
The component parts for the early Colt Hartford-London Navies were manufactured in Hartford with the parts being shipped to London where they were assembled and finished at Colt's London factory.
The First Model London Navies are found in the serial range of 1 through to 2000 with brass back-strap and small rounded trigger-guard. A few will also be found with a brass square-back trigger-guard and are considered a rarity.
Many of the First Model revolvers have the barrel address of ‘ADDRESS SAM'L COLT NEW-YORK CITY’ with a dash at either end. They are interspersed with ‘ADDRESS. COL COLT. LONDON’
I like the checkered grips.
I'd also like to see the "wooden box"
- since it could double the value of the gun.
The large hole in the LH side of the cylinder frame looks like the upper mounting stud(s ?) for a detachable buttstock have been removed (there should have been a 2nd stud on the RH side & a notch in the bottom of the gripframe) - is there a buttstock extant somewhere ?
You're gonna want to look over this link to London Colt's thoroughly: http://www.coltcollectors.com/models/04-5b-063.shtml