Hole Behind Timing Sprocket

Tearing down a '90 4.0 for a rebuild, I pulled the timing set and noticed a rough opening in the block casting at the top of the area behind the cam sprocket. It appears to have been cast there, but the rough shape had me concerned. It's about an inch and a quarter by 3/8ths, just inside the sealing surface for the timing cover. It opens into the lifter area, and I see there is another opening at the rear of the lifter galley, I guess to drain away excess oil? Anyone who has done a rebuild remember seeing this? Thanks!

Got a pic of the hole. Dosen't look like anything broke through, but just concerned because it is so irregular shaped. It does not go through to the cylinder.

I'd guess it's there to let oil run down onto the timing chain? It's probably just a rough hole from being cast and they don't bother machining it nice and clean.