Could anyone tell me if the updated Mercedes B2 valve kit does not require the use of the lip seal with the plastic sleeve?

If you are speaking of the B2 Piston my understand is the Nylon piece replaces the metal tube piece pictued behind the Lip Seal in this thread below; and that you still need the seal.
B2 Piston Woes (maybe)

Within the last 2-3 months there was a Thread and Brian posted a parts Brekdown of the stuff needed.

I found this in my notes but do not know where it came from:
B2 Piston Seal
The only part #'s I found for the piston lip seal ring are # 1242720255 and Genuine Mercedes # 124.272.02.55. you should verify with the dealer!
The new plastic bushing (126 277 08 50) goes into the bore small end first, with the thin small shoulder outside. The new lip seal (006 997 73 47) then goes into the bore - lip facing outwards - to hold the plastic bushing in place. It's then obvious that the plastic bushing is what locates the small polished end of the B2 piston in the center of the bore; the lip seal's purpose is only to prevent trans fluid leakage from the bore into the area where the B2 band and apply pin are.

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84 300D, 82 Volvo 244Gl Diesel