Vortec 4.8 vs LS1 bellhousing pattern?

[yossarian19]

Ok, so, I bought the engine & transmission for my truck separately.
The trans I bought, I was assured, came out of an LS1 equiped F-body. 4L60E.
Everything bolted up to my 2002 4.8 just fine, except one hole on the trans that went to an un drilled blank face on the engine. I remember reading somewhere that you def. don't want to drill that hole.
But... is this a Gen I / II transmission? How would I tell the difference? Seems like all Gen III motors should have the same lugs for the bell housing, right? Or do the trucks just have one less bolt in the transmission?