45acp Colt Barrel Marking

Found a barrel in my parts bin. Only mark is a #8 laying on its side on the left lug next to the chamber on the area behind the barrel link pin towards the chamber end. The barrel hood is black and matches the finish of the barrel. Its never been installed and looks new. The bore is something really amazing and highly finished with absolutely no tool marks.
The reed ramp has not been altered.

Just to see how it fit I tried to install it in my 1911 Colt. It was a little oversize and would not enter the slide.

Most of my parts came from a man that built the AF Premium grade 45 automatics. We were friends and he would go through his parts for sale and pick out the good stuff for me to buy. Cant remember buying this barrel but my guess is it came from him.

All I can figure is the #8 is the identification of the machinist that finished the barrel and it never went to be proofed and stamped with the manufactures name. I think its dimensions are oversize and it would have to be fit to the pistol and dependently not a drop in barrel. It does have the like and pin installed.

Any ideas of what this barrel is? I don't know how to post photographs so will ignore the chime in about posting a photo would help. Its just a barrel with the #8 and no other markings.