73 Merc 850 lower unit hole

[ShowMeGuy]

I have a 850 lower unit that was a parts motor/spare that is no longer needed as the Boat/Motor it was sparing has been sold. I am looking to sell this Lower unit but wanted to make sure it's in good order prior to advertising it.
There is a hole about the size of a coffee stirrer that goes from the front of the upper vee into the area where the shifter is in front of the water pump. i will work on getting a picture tonight but I was wondering could this be filled in with marine tex, sanded and painted or is the housing scrap material?

 

[GA_Boater]

Without pics, it sounds like it might be a speedo pickup. That's a pure guess.

 

[Chris1956]

I did not think they had speedo pitots on those old gearcases. Is it possible the gearcase is newer? A '73 Merc 850 usually has a flush plug that allows a garden hose to push water into the side of the water pump. You have that?