Ok, cliff notes. I booked my jacket sleeve on the one in the engine when I was changing the fuel pump a while back. It broke it off right the little bubble. I used a bolt extractor and removed the little stub left in the block.
Since then, I have tried two part store replacements that are said to be for the poly, both too big, a good 1/8 inch bigger diameter on both ends. Same with the Chrome Direct Connection LA dipstick I’d bought off here a while back. I tried a factory 318LA from a spare engine as well, no such luck. Unfortunately my spare poly is already missing the dipstick and my wanted ads have gone unanswered.
So I’m thinking I either braze the poly dipstick back together, or braze the dang thing to the block somehow