Mounting plate & stud - small older 4 section Gitzo tripod

Have an older small 4 section Gitzo tripod. It is "GILUX TATALUX" on the platform.
Am in need of a mounting plate and stud.

The top is 2 1/4 inches across. Has the small stud sticking up on the platform to keep the mounting plate from turning. The mounting plate stud goes through the platform into the center column.

Am having no luck with Gitzo/Manfrotto looking for a piece that fits.

Anyone know where I find the part fo this old, small tripod? Would like to get it going for the lightweight gear.

No idea.

But if you have metal workshop at home (or a friend has), just cut a thick aluminium plate, cut a 3/8" thread and cut off a piece from a 3/8" threaded bolt to form a stud. Glue some rubber sheet on the plate.
The original stud though was twin threaded. But the smaller 1/4" thread is only needed if a camera would be directly screwed onto the mounting plate, or if a very small head would be used.

The mounting plate itself is likely redundant, as with a 3/8" stud one can screw-on a 3/8" head with flat base directly onto the end cap of the collumn.