I have the original Spec & drilling sheet from the Power Surge. It shows the same drillings. These days, I don't think this is anything special. It looks something like this:
Title: "Drillings for Pin Out 4-6". Top wt. 1.5 - 4 oz."
Exact Description from the sheet: HEAVY OIL "Pin 4.5" from PAP, CG 4" from PAP and 1.5" - 2" below center of grip. Position X-Hole (weight hole) over 6" and 2.5" down"
P is pin, F is finger holes, T is thumb hole, A is PAP, C is CG, X is weight hole.
--------------P-----------------
-------------------------------
-------F---F-------------------
-------------------------------
-------------------------------
--------------------------A----
----------------C--------------
-------------------------------
---------T----------------X-----
Description for Medium Oil:
"Pin 5.5" from PAP, CG 4.5" from PAP and 1.5" - 2" below the center of the grip.
Position X hole (weight hole) over 6" and 1.5" down."