This is some information another gentleman gave me regarding these pistols. I thought I would pass it on.
"Interesting piece of history - these were not copies/knockoffs. These were made under license from Colt for an Argentine govt contract, and were actually produced using Colt tooling that was shipped to Argentina for the contract.
THe FMA on it stands for the Spanish equivalent of 'Factory for Munitions and Arms', which was the government arsenal that got the contract.
You might want to google them, and post some info on their background, it'll get people's interest up more than if they just look like south American 45 knockoffs.
If I recall, (pleasse verify, as my memory is vague), up to SN 50,000, they were actually made by Colt here in the US as the tooling was being shipped, and workers trained, then higher SN were made there, but I could be wrong on the SN. If I'm not, it says both of yours were made in Argentina at 53xxx and 110xxx"