Just in case anyone is ever trying to identify an F series TRD centre, here's some handy pictures. The part number is: 41301-RA010





There's also some confusion about the TRD centres being swappable from 1.5-way to 2-way, but the F series diffs at least are limited to 2-way only. There's a note on the TRD parts page about all of the FR diffs being 2-way only as well.