0.7498" +0.0002" / -0.0000"

I have other drawings as well, I just don't publish them.
I'm actually drawing up all the Govt profiles as a reference to compare my profiles to.

Quoted: but when you buy front sights or gas block they are referred to as .750, .625 and .920

Mostly correct.
Front sights and gas blocks are all made to nominal dimensions such as 5/8" (0.625"), 3/4" (0.750"), 7/8" (0.875") or 15/16" (0.9375")
Most front sights are made exactly to the spec with a reamed hole while most gas blocks are made a couple thousandths oversize and attach with set screws.
Barrels are usually made a couple ten-thousandths UNDER the spec to allow fitting a reamed hole that's right on the spec.
The 15/16" seems to have morphed into 0.936" although there are gas blocks as large as 0.940" as well.
Bull barrels are usually 0.920" out in front of the gas block.
I think that's where you got the 0.920" dimension, or from the world of 10/22 bull barrels which all run 0.920" as well.