Somewhat stumped, 753 engine oil leak

Hello friends,
I've had this machine with 2700 hours for many years.
It has a slow seepage of engine oil on the inboard side of the engine. It definitely is not the valve cover as I've changed this. In the pic you can see it's dry at the valve cover, but wet around the front cylinder exhaust port. I've changed the timing cover gasket too. There is absolutely no loss of function or power, this beast runs strong always. I suspect it's the head gasket. I've never been inside the v2203 kubota, but for those of you who have, is there a pressurized oil passage in block to head mating in this location? If you've seen my posts on other issues, you know I'm mechanically adept, but never had to go into a diesel engine before…I have rebuilt many gas tractor and car engines. Any specific tips to offer if you agree it's the head gasket, if I dive into it?
Pic is from under lifted cab, looking at engine.
Thank you in advance

Btw no coolant leaks. No coolant in crankcase oil. Not burning coolant.

It is coming from that plastic cover. That is basically a hole plugged with the rubber plug. You probably have some blow by.

FWC…thank you, Im pert near sure that is a freeze plug. I will take a closer look.
Here's a clean pic from internet(someone else's engine)

Markle said:

FWC…thank you, Im pert near sure that is a freeze plug. I will take a closer look.
Here's a clean pic from internet(someone else's engine)

Click to expand...

No it is not at freeze plug. Its where you could put the dip stick in. Depending on the application either this side is accessible or the side where your dip stick is right now.

Which part ?, see engine parts list pic which shows side with my issue.

It is not in that Parts Break Down, what is your Serial # I will look it up.

Sn 508611665 thank you.
I opened the oil fill cap while running.
No appreciable blowby.

Markle said:

Sn 508611665 thank you.
I opened the oil fill cap while running.
No appreciable blowby.

Click to expand...

It's Part 11 on that break down

So if I understand correctly, it's a plastic plug covering the unused optional site for an oil level dipstick. Might have popped out from internal crankcase pressure.

Markle said:

So if I understand correctly, it's a plastic plug covering the unused optional site for an oil level dipstick. Might have popped out from internal crankcase pressure.

Click to expand...

Correct