It is clean. it's in mint condition as it was when new a few years back and has had this issue the whole time.

Either way it doesn't change the fact that from new the two part cannot be fitted together. I stopped buying MTC after that since the build quality is noticeably worse than my original viper. If you ever had the need to take a file to a £250 optic when it's new out the box it's time for a change of manufacturer.

Sadly i have purchased a £300 Niko recently and found that has appalling build quality compared to 3 others I own from about 15 years ago.
I don't know what you have to pay to get the same level of build and optics these days but either the manufacturers are sliding or I don't have the cash for nice glass anymore.