Seems that Jim Arnott and Mike pollard collaborated to measure up the studs that goes in the rear of the slider door on early vans that the handle attaches to .  Jim sent me the sketch a while back and asked me to make a pair.  I finally got around to it, I made a model from the drawing ( and I made another drawing) and then machined out a pair 

Pics and the step file and pdf of the drawing here

https://shufti.blog/2024/05/27/vanagon-pre-85-slider-door-rear-handle-stud/

Alistair