Quote Originally Posted by titsonritz View Post
I bought my two directly from Magpul back in December 2019.
Quote Originally Posted by Sparky5019 View Post
(snip) The tube I have are super smooth inside but these are the latest runs that I bought directly from magpul several months ago. There could be older versions floating around too.
Similar to titsonritz, I bought my Magpul extension directly from Magpul shortly before I posted the photos (early 2020). It's not "oil or photo artifact", it's roughly finished metal. Like I stated in the original post; don't know what effect, if any, that might have on function.