I can see something inside the tube in the region the butts would be. It looks like a change in surface finish but is probably a butt.

I have a small milling machine and will see if I can set up a 'quick and dirty butt tester' (I am not going to google that phrase) and measure it accurately. A bar with a rivet in the end clamped on a v block and a DTI in the chuck should do the trick.