Think my TS55 is about 15yrs old, I needed a new base because the old one was worn.
I found the base I thought I needed on Ekat and called Festool (UK) to confirm but they were a bit none committal. When it turned up it fitted fine, the gibbs (is that the right word?) underneath were much improved from my old base but apart from that I think it was the same. It came with a few bits of plastic attached like the bevel scale. I actually found it a real faff to set up properly for the offset from the rail.
Pretty sure the base for the TS55R is different, different Ekat numbers anyway, doubt it will fit but you never know.