[Phono-L] Advice please - holes in cylinder surface

[Bruce Mercer]

I saved the photo to My Pictures and looked at it extremely blown up. There 
is a dimple in the bottom of each hole. It looks like it was done with heat 
and ???
If they were bubbles I don't think the perimeter would be that perfect or 
have that mark in the bottom of each hole. One hole appears to be 
'starting'. They look like BB holes until you look closely and see the 
dimple in the bottom. You can see a stylus drop above one of them.
Bruce and my .02