k1 spring kit and piston

[V1uhoh]

I have a 1987 Porsche 928 with the Mecedes 4spd automatic transmission. (Porsche type A28) The car has 157k miles on it. The transmission has a slight flare on the 2-3 shift. My friend with a similar car had the same issue and after searching this site we saw the K1 spring kit upgrade. We did that and am happy to report the flare is now gone in his car.

While we were replacing the spring kit, the seals on the green "piston" assembly shown in the pics looked a bit worn. I would like to replace them or the piston when i do my upgrade next week.
The part number is shown for the piston in the pics below, however the local MB dealer cant find it in the part data base...neither can Porsche.

is there a seal kit that would address this or does a new piston come with the seals on it. Where can i find a new piston if so.

thanks.

the part number on the piston appears to be 126 27 09 32 We tried variations of that to be sure..... 00 32, 99 32 etc etc No luck