Hey John.
A google search should bring up some convertibles, as there are at least 4 on the road at the moment.
There were several convertibles back in the 60/70's and most have not survived.
There is one that is believed to be a survivor and not a recent conversion.
It has some specific mods that could be compared.
When first put back on the road after being found in a chicken coop.

A change in paint colour.

I believe this is probably the same car today.

Do you have more details and/or photos?
Colour? mods? etc.
Regards
Alex