[p144]

I looked through the UCE shop manual, but couldn't find a specific picture of this part of the side case where the oil filter goes. I noticed it looked oily down in this area and once I cleaned it up it looks to me like a broken off screw missing the head. Am I correct, or is this how they all look?

[Arizoni]

That is an expansion plug, used to plug and seal the hole that is drilled from the oil filter cavity down to the crankshaft oil supply hole that lines up with the end of the crankshaft.

It consists of a hollow aluminum plug with a tapered pin in the center.

The counterbored hole it is in is slightly larger than the hole that is drilled down to the crankshaft end.  This counterbored hole also has a very smooth finish.

To use the plug, it is inserted into this counterbored hole until it bottoms out.  Then the tapered pin is inserted into the center of the plug and driven down into it.
This expands the plug tightly against the walls of the counterbored hole.

Plugs such as this can easily seal pressures of up to 3000 psi.
They are often called "Lee Plugs" as a company by that name developed and sells them in all sorts of sizes.

If that was too much explaining, the quick answer to the question is it is normal.  Don't worry about it.

[p144]

Ok, thanks!

[SteveThackery]

That is an expansion plug........ It consists of a hollow aluminum plug with a tapered pin in the center....... Plugs such as this can easily seal pressures of up to 3000 psi.
They are often called "Lee Plugs" as a company by that name developed and sells them in all sorts of sizes.

That was a totally brilliant post!  Thanks, Arizoni - I've learned something new today and haven't even had breakfast yet.