Thanks Major and ccongrats Dusty: you got yourself a nice regular New Model Army, 3 variation (Colt-type naval scene on cylinder), probably 2nd sub-variation (if the cut for the sholderstock is present in the butt, if not it is the 3rd sub-variation).
Probably made 1966, by Fabriques d'Armes Unies de Liège in Belgium. As the next lower S/N we have # 4601 in our survey which has the plain, rebated cylinder (regular NMA, 1st variation) reported from Germany, and the next higher S/N we know is #4686, also a 3rd variation/2nd sub-variation like yours reported from the USA.
The * over S (sideways) is the mark of the inspector of the Liege Proof house. It stands for Charles Daenen who served there from 1952 to 1968. Please, check www.1960nma.org
for further details and please, please, download the questionair from the website, complete it and mail it to me with the specifics of your rare Belgian Colt...because I want to include her into our survey (without your name, of course) if you are agreeable.
Please, feel free to send me a PM if you like to have further information.
Long Johns Wolf