I don't see any manufacturer marks in the photos you supplied. Look on the underside of the barrel, on the frame under the front of the trigger guard, on the trigger guard and backstrap under the wood, and on the butt of the backstrap. It has both proof marks and a date code (XXIII/1967) which is not indicative of a "kit" gun but one that the manufacturer sold on the market as an assembled revolver. The load lever pivot screw is a replacement, looking at the head finish and the end of the screw shaft. The barrel address is not the same as a 20th Century Colt 2nd Gen (et al) and is one I have not seen before. If it has a DGG (sometimes in a circle, sometimes not), it is an Armi San Paolo [although I think that ASP produced only copies of the 1851 Navy, 1860 Army, and Remington "1858" (of which I have one, AH/1981)]. If it has ASM, S. Marco, or a stylized ASM as an equilateral triangle, it is an Armi San Marco.
To the best of my knowledge, only Uberti and ASM produced Dragoon revolvers during that time period. Uberti always used the "S"-type load lever latch, while ASM used the better horizontal "Navy"-type latch, which yours has. Historically, the horizontal latch only appeared on a very few original late production Colt 3rd Model Dragoons.
I am leaning toward it being an ASM.
More photos of the various areas I have pointed out would be helpful. At any rate, good luck with your quest!
Regards,
Jim