Nope! I've never seen one like that, but I'm no expert. You either have a rare piece or someone switched it out. I think they closed AA in 1955, don't know when the last 1911s were reworked there.
I have seen a bunch of 1911s that the front sight was not correct. I guess they have a tendency to fall off. The orig. 1911 front sight is hard to find so people ground a 1911A1 sight to fit.
Finding an orig. rear sight? Might try Numrich or sarco? and thats assuming the groove hasn't been altered to accommodate the sight thats on there now.
How hard would it be to rework the sight you have? Remove the dots? If you find out for sure its not orig.
If I remember right, the Govt. released a ton of the AA marked 1911s from storage back around 1970 or so. They were like 50 bucks and people did some strange things to them.
Here is a AA marked Colt 1911 from 1914 I picked up earlier this year. Does your rear sight have the same profile? Great old weapons! Good luck with your project. Ken
U notch rear sight.