I think Corbin is more Harley oriented and beemers are a side-line. Or perhaps you're right, no one there speaks english except the receptionist/phone answerer.
The CS uses the same seat as the S. CS stands for Classis S, and was pretty much a 90S except for snowflake wheels (in the US, wires in other parts of the world), and Bings instead of Dellortos.
The T, however had the non cowled seat and was probably the last to use it. The non-cowled seat, though fits on the bike, is totally different. It's like the /5,6,7 seat.
I haven't been to the LaMay museum either, but have heard of it. One of these days I'll get up that way.