I had an old 1980 600 EX crankset with the 6mm hex self-extractors.
Don't which version Shimano phased them out.
Suguino made an aftermarket set of self extractors (Autex) to retrofit to Shimano and Sun Tour cranks. They consisted of replacement dust caps, 6 mm hex key bolts and a thrust washer to go between the bolt head and cap. I fit them to my S&S coupler equipped Co-Motion travel bike so I could remove the cranks for packing if needed. The cranks and bottom bracket (105 8-speed triple with a UN52 bb) came with ordinary mounting bolts.