7790314 means that the slide was produced for the military, this particular one was produced by Colt. Colt first started to make completely heat treated slides for the military in 1947. More recent production 7790314 slides have been made only with the number on the left side of the slide and a small TZ on the right side of the slide. The TZ slides were not made by Colt. 7790314 slides are also referred to as "hard slides."
I like the Colt NM slides....... they’re pretty cool.
It’s interesting to note that Colt also made a limited supply of those slides with commercial Colt markings on the left side of the slide instead of the federal stock number. Armand Swenson (among others) built a limited number of guns using those commercial NM slides and I have been told he thought very highly of them. Provided they are in good condition those slides can help make a pretty unique custom gun.