Colt 1911 serial dating
I have a frame with a 4 digit number, under 2000, which is a Remington Rand made in about 1920.If it were a Colt, it would have been first contract, Navy, 1912!
The pistol shown appears to have had it's serial number removed. That said, pistols that had their serial numbers removed and never returned to the government could have also had an X prefix serial number added by anyone in order to give it legitimacy.
Since the new serial number was issued and applied by a branch of the U. A close examination of the pistol shown might give clues as to whether it is legitimate or not.
The pistol shown falls into the serial number range from approximately 500000 to 629500.
So this gun looks proper, rebuilt at Springfield Armory probably in 1925, was most likely originally manufactured in 1919. That is certainly in line with what I posted, except the pistol shown appears to have it's serial number removed in some method other than sandblasting.
That was the reason for the caution about the X serial numbers being added to stolen pistols with the original serial numbers removed by their new owners.