[78-L] One or three holes?

[Milan P Milovanovic]

Dear members,

not so while ago, the discussion about details of lathes raised. I came across this record sample

http://youtu.be/tc2FrjRa9Os


It is clearly visible only one hole mark besides spindle. I always thought that one additional hole on lacquer was reserved for amateurish type media and three additional holes for professional blank samples.

Someone knows what's in case here? Why is there only one? Could it be possible that recording engineers used semi pro or amateur recording blanks?

Thank you!

Best wishes,

Milan