Any experts out there who can verify a part number?

They look like tinnerman nuts.

 

They're just hex head screws with a big captured washer. 7mm heads if I remember right. They thread into the springy clips on the front of the pan. There's one at each end as well.

 

I think he was talking about the blind nuts, back when we had hardware stores, a grumpy old clerk called them Tinnerman nuts. AKA Springy things.

 

I guess i should order a spare belly pan for future use, while still available from dodge for my antique.

 

Didn't recognize them in your pic (guess I've removed same during oil changes). Some mfg's have an under belly door for oil pan drain bolt access (only makes sense I guess for vehicles with oil filter top side) making it less cumbersome than having to remove the entire thing. We'd need an additional door for filter access (so ok Dodge engineers that would be expecting too much).

 

Mine has a small pan beneath the front pan that allows access to drain plug, and filter with 4 10MM bolts. So easy to do with a Milwaukee 3/8 drive power socket wrench.

 

Yeah, the one you remove for oil changes is behind the pan I replaced, and yes, it's the one with the 4 10mm bolts. It looks like this:

 

Update:
I couldn't live knowing that the old one had plastic pins holding the air ducts and the new one didn't. I just had to pop those out of the old piece and use 'em on the new. Here's the pins and as far as I could tell, a 3/16" drill was the right size:


Here's the underside before:


Here's with the hole drilled:


...and here's with the pin in place:


Now the overly anal other voice in my head is at peace.