Don't even fret with the tube... it will be bare in a couple hundred rounds or less and a well worn mag tube is equal to a marksmanship badge
... I wasn't trying to imply the wear is excessive... just "well broken in" rather than "slightly used"...
Mine is 20 years old with untold thousands rounds and receiver is fine... but my tube has looked like yours since it got the first few hundred rounds thru it....
For "pitcher day" take a
FAT TIPPED sharpie marker to it and it will look "maiden fresh" until you shoot it again
Brent