Mystery New Yorker Part

Alright Mopar sleuths,
I've been searching high and low for this part and I can't come up with it anywhere, and unfortunately it is keeping me from being able to drive my car too much because of fear of the driveline being damaged. The part numbers (or as close as I can figure them to be) are: 9-71-15 (Rubber Stop for rear mount) and this odd bolt with two built on washer part 9-71-18. Any and all hints, suggestions, or clues are appreciated. Meanwhile, I'll be digging through boxes at Mopar Nationals this August to try to find it.
Thanks!
Author: Valent64