My football jig mold has a strange weed guard and it is much smaller than a normal base pin, BUT what I have found is I have a drill bit (sorry have no idea what size) that fits perfectly into the weedguard slot, and even though it is small it makes a nice pilot hole for a drill out after I pour/powdercoat them.
Note: I use the smooth end of the drill bit, not the blade end.
Hope this helps!
(I really shouldjust buy a new football mold, but once something works, my cheapness really shines.)