GMC 230 inline six weird hole/oil leak, please help ASAP

Just picked this truck up and got it goin, 230 6cyl/3spd manual. Drove it around for 15 mins and found this oil leak after being parked for about 10 minutes, it seems to be comming out of a very small hole that looks to be factory, is it a saftey hole to show that it needs a rear main seal when oil is comming from it? accidental hole that should be plugged? Its right after the oil pan, here are two pics, you can see the small hole in the 1 picture. Thanks, Matt

 

yep, thats what it is

 

ya its been sitting till i got it, so rear main seal needs to be replaced?

 

Judging from the amount of oil and crusty buildup on the crossmember it has been leaking for a while. Pull the pan and replace the seal check out the bearings if they are worn a new seal wont help anything. OldWolf