Late Colt stocks have wide rings around the holes. Your narrow ring stocks probably have a K and a star on the back sides, which would indicate they were made by Keyes Fibre for a Remington Rand, Ithaca or US&S pistol.
What does the top of your hammer look like? Serrated or checkered? A photo would help. And yes, your magazine is incorrect for the pistol as manufactured, but it may have been with the pistol for a long time.
How is your barrel marked? What does your mainspring housing look like? Photos would help.