Now days, some folks complain because there's too much writing stamped on the reproduction guns. The stamped lettering makes it look less authentic and the manufacturer was trying to produce a more realistic Colt clone. Many historical reenactors feel that the less stamping there is the better.
In a way it's similar to how there's often not any specific history attached to an authentic 19th century Colt gun, i.e. who carried it, where and what it went through after it was made, shipped and sold. Because the individual history of most old guns is lost it just becomes an old gun subject to one's imagination.
I had a steel frame, .36 1851 Navy with a brass guard and back strap - it had the same identical markings as this one does. I disassembled it, went over it with a fine tooth comb and never could find a manufacturer's mark on it. The quality of the brass castings was better than this one but overall, if you put the two side by side, they would look like twins with the exception of the guards and backstraps. I believe the date code on mine was the same as well. I did some horse trading in the 70s to get it and it was new but didn't have a box or paperwork with it. I traded it off this last summer towards a 38 spl Colt that I wanted as I have other '51s that I liked more. It still remains a mystery to me as to who made it other than I'm sure it was Italian. I have several ASMs from that time period and the fit/finish was much better on those but who know? I always figured it might be a Pietta but that was a stab in the dark. Good luck on this one - I hope you're able to find something out on it. Enjoy!