It's probably close to being true.
At any rate, it's rare.
My first T-Bird was a 1960 with a 3 speed manual on the column. I owned it from about 1967 to 1969.
Here's another thread where I posted a photo:
Unfortunately, I'm not sure rarity (in this case) makes it any more "valuable" than a hardtop with AT.
In fact, it was horribly inconvenient because it was not syncromesh and I had to come to a complete stop to shift back down into 1st gear.
Probably worth getting just for the bragging rights.
Then upgrade the tranny with a later syncromesh 3 speed.