Hey John!
Like I said in the email we are happy to take care of it however you like. If you want to replace it, its no prob. I have them in stock. If you want to shoot it first and then decide that's fine too! Whatever is best for you.
Again not sure how that one got through after drilling. Definitely NOT our standard. Gas port size you are bang on though .096 is what we drill them at for .308.
We do not make the extensions just so you know. I cant really see what you mean by burrs on it but none the less if you aren't happy neither am I. The extensions come from the same US manufacturer that makes extensions for a multitude of other companies. As with anything AR a couple shots and most burrs get smoothed out in a hurry.
Happy to proceed the best way for you.
R