[C_Ben]

Hey Sam... did you find something suitable for this? I can check my microfische catalog this weekend for an OE part number and get back to you if you have not. I see the aftermarket head gasket sets do not seem to include these. I do remember seeing these when I took apart my rocker shaft assemblies. Such a pain to do with only 2 hands sometimes. Where you from by the way? Was it the common external coolant leak? Where are you from? Are you going to keep the dual EGR system on the truck when you put it together?

 

[C_Ben]

So I dug out the microfiche machine last night and found the O-Ring part number. I didn't rememebr you were looking for two types of parts as the "inserts" are different as you point out.
So I started searching the O-ring part number with not much luck, I came across this website which seemed to match my microfiche card.

https://partsouq.com/en/catalog/genuine/unit?c=Mazda&ssd=%24%2AKwHf6_rpiYGAm6-ArLzT44eTs7Sqk4-EjdH6ltySjZitmZWA2NzKrd_Y0trZlZrR2ciCrNrY3dyql8PTlK3e0wAAAAA429Eb%24&vid=1927233777&cid=481&uid=27506&q=

I belive you need for the inserts:

813012174

PLUG,ROCKERSHAFT

and 8173-14-323 for the o-ring.
MAYBE a mazda dealer might have this around somewhere. Another source would be to find a 1982 ford Courier parts manual and perhaps available with the Ford number. The O-ring could probably be matched up. The "inserts" may prove difficult.
Also of note there is a bulletin referenced in the lower right of the exploded diagram found on that link.