I don't have any pics but i would like to know if anyone has built an AK with an extremely pitted gas tube? Did the rifle still function?

A new gas tube is not that easy since it is on a Tantal kit. A decent matching number  albeit well used kit. I have not had time to really get out the flashlight to check but on the first inspection the gas tube and gas block seem to look like the surface of the moon. I don't think any of the pits go all the way through.

So what say ye?  Build it or part it out?

build that bad boy

I'd sand blast it, use some naval jelly on it and maybe fill in some of the deeper pits with JB weld.

You';; notice that even in a new one that the gas piston isn't exactly a precision fit.....I don't see where it would make any difference.....