Head shave question.

Bought a "machine shop fresh head." I know it has been cut but l have no idea as to how much. It is a drool tube head. I was told it was done 25-30 years ago so no known knowledge nor paperwork exists of work done that l know of.
Is there any way to tell approximately how much it has been cut?
I can CC it but have not done so as of yet.

Is there any correlation as to amount of cut ie: 10 thou, 40thou, 80 thou. To CC?
Like as in 10 thou = X amount of CC
60 thou = X amount of CC

Combustion chamber has been smoothed a bit.
I need to pop the valves to see if any bowl work has been done.
Just looking for ideas before setting aside time / money to have ( or not have) any more taken off.