Yes, SX has straight tone holes, SX R rolled ones. Maybe drop Steve a PM to see if he's seen any SX's with warped holes?
If you're adding Keilwerth to the list of possible tenors, I have a theory that Hanson may have a connection with Keilwerth so maybe add them too? This goes back to my thread here:
http://cafesaxophone.com/threads/well-well-my-new-hanson-is-a-buffet-400.11107/
Bearing in mind Alastair is a consultant to Buffet and told me himself that the SA5 is a Buffet 400 in disguise, and that Buffet own Keilwerth, and that The SA5 body is made in Germany... well, elementary!
Why not phone Alastair, explain your search for a tenor, possibly an SX90, and he'll soon volunteer whether that has a connection with the ST8 or other of his models. Just an idea....