Hmm-gotcha. Well, if you plan on pulling the crank out, check the casting number. 2M = 28oz; 2MA, or 2MAE = 50oz...
If you plan on throwing in a stroker crank, all the kits I know of use a 28oz imbalance unless, (1) you "0" balance it with mallory metal...a good idea, but time consuming and expensive, or (2) drill the hell out of it for 50oz...which I've seen that before, but I wouldn't really recommend going that way.