The S54 trannies on the BEAMS Celica either have helical LSD, viscous LSD, or no LSD, and afaik all the ones on the BEAMS MR2 have the helical LSD (like mine).
I know he has it from an ST202, so it still could have it. I'm not saying that it must have it, just that there is a chance (because it was an option on some ST202s, not just the BEAMS ST202)