It's "just" threaded in to the hood, with the spring and big hand-turned adjusting nut that run up and down the threads.
Those springs and nuts are often usable, while the actual shaft gets rusted solid to the nut inside the hood even more often it seems.
The one on my '71 is free turning because I got to it while it was still young and lubed it. The '68 was not so lucky and I can't turn it to save my life. I can wiggle it and feel the big nut plate or whatever it is up in there, but not turn it.
Gonna have to make a special tool I guess.:-[
Looks like you're calling it the right thing eoth (
http://www.wildhorses4x4.com/product/Hood_Pin_Spring_Assembly/Hoods) so if it's available locally, that should get something to come up on the computers.
I'm betting it's the same as many trucks, and even vans and cars (check on a '66 Mustang for instance) of that vintage.
If not, have one of the vendors put one in the US Mail for you to save on shipping this small and light part.
Good luck.
Paul