If you convert the A/C on a W126, do the flush, the whole thing - do you need a new pressure switch and/or temperature switch?

I found many of the parts now to be both R12/R134a. I had a "professional" conversion done. He did the receiver/dehydrator (obvious), flushed the system (o.k., one step above obvious, but the most important, and he did it), did not do the rest of the o rings (I ended up doing them with the generous help of CTaylor of this board at his home garage), but it seems now he also did not do the switches.

I know this is a controversial topic. Whenever I order a part, though, I am told it works for both refrigerants. This includes the receiver/dehydrator and the expansion valve. Anyone with experience on the late model 126 want to chime in?

Thanks!

__________________
Henry Bofinger
1989 560 SEL (black/black)
2001 Audi TT Roadster (silver/grey)