I have noticed that every third generation Colt that I have ever taken apart has the same little problem regarding the trigger screw hole.
The slot for the hand always intersects the screw hole leaving a bit of a hole in the thread area. This leaves the trigger screw slightly unsupported in effect although I don't think it matters.
I have a 1977 third gen that has this problem but it doesn't affect it to my knowledge.
Is this common on 1st and 2nd gen guns?