Got to checking out my spare today, the good news was that all the codes and marks were present as well as the date code on the tire thats matches my build. The unfortunate issue is the tire is deformed. As seen in the attached picture the sidewall normally folded internally protrudes out.

Is this simply caused by someone having used the tire years ago?

I tried a few things unsuccessfully and would like to know if anyone can rework this condition?
Or has anyone reworked one successfully?
If so how ?

Thanks for any suggestions

Do you have a vacuum pump that you could attach to the valve stem. That is what comes to mind in looking at the tire above.

are you really thinking of using it? mine are so old I would not even attempt putting air in it.

I had a once inflated space saver that I tried airing up, then deflating, hoping it would go back to original configuration.
It didn't work, so I aired it up again and let it sit 24hrs in hopes it would stretch, then fold back like it should.
Next day I opened the door to see a space saver that had blown the tread off.
Try a vacuum pump.

LOL, glad to see my fear is confirmed, I pulled the valve stem and put the rubber tip from the blow gun to it yesterday with similar hope that it may somehow miraculously return to proper shape. I put a couple PSI at best and watched my buddy run to the other end of the shop laughing and asking if I was seriously going to try putting air in that thing.

There is no air in the photo above, thats just the shape its holding.

And the answer is that under no circumstance would I use a 45 year old tire for anything but a pretty picture.

It's apparent that the space save in my convertible was used at some point, but it looks alot better than that one.
I don't know any way to fully restore a used space saver back to its original shape. My understanding is that once one has been inflated and driven on, it is permanently deformed.
Best bet I think, would be to completely remove the tire from the rim, try to manipulate the tire back to its original shape, and reinstall.
I put together a compact spare for another of my Challengers. Someone here sold me a rim, and I found an old, tired, but never used correct tire from some Ford guy on ebay. Seemed like an easy task to install the tire, but was anything but. My friend Gary had a tire machine in his shop. We wrestled with it trying to get the tire to seat. No dice! We found an old thread by the late Jules here about installing space tire tires. It required inflating the tire, then quickly deflating it. I was nervous, but we inflated the tire, which blew up to a regular 78 series size! But the bead seated, and we deflated it. I rolled the tire around on the ground a bit to get the shape back. It looked pretty good. Here is the tire from my vert that has been inflated.

Here is the one that I put together for another of my Challengers. The tire looked pretty ancient, but amazingly looked better after we managed to install it on the rim than it did loose. Thanks again Gary for the help!