My impression is that Sunn wasn't particularly careful with cosmetic stuff. I figure they decided to upgrade the looks with the red stuff about the same time they changed the circuit to add the mid switch. The red stuff arrived while the original T was still on the assembly line, so at least one got made with the red knobs, etc. When the new amp was started, they discovered that they still had some of the old hardware, and at least one got silver and black stuff. No big deal, really.
