Hey Mike, I remember you. Sorry you've been down. I don't know how old you are but I know it takes me a lot longer to bounce back from aches and pains now that I'm in my 60s.
As for a jack, I have the one that was in my car when I bought it. Original or not, I don't know. If you want '68 specific, you might try Kurt, aka 68GTOMN. I think you know who I'm talking about?

Hey Greg, This is Mike Smith over in S.C. Haven't talked to you in quite a while, but had a terrible accident about a year ago and broke/fractured my hip and femur bone. Been an ordeal. Just begining to walk a little. Reason for my note is I need a bumper jack assy to go in the trunk on my 68 GTO. I need the complete unit, base, jack handle, and hold down parts. I had no idea this would be such a hard part to find. I was wondering if you had any ideas? Thanks, Mike