What does Affordable Cases say about it? The first thing I would do is call
them and ask what the differences are, tell them what you have, ask them if it will work, and make sure you can return it for a full refund (including return shipping) if it doesn't.
Their return policy seems a bit ambiguous, and even
they suggest that you call them first;
"Please contact us to clarify any questions about the model of your equipment before placing your order".
http://affordable-cases.com/index.php?main_page=page&id=1Reading their warranty, it doesn't seem like the opinions of posters on a Sunn forum will guarantee they will take a return. I think your question is better asked of Affordable Cases rather than here; but hopefully one of the forum members will have first hand experience with them to share.
While you have them on the phone, ask them what a "Sun Supta vintage 1968 Head" is.
By the way,
was there a
1972 Model T? I thought '73 or '74 was the first year for the Model T.