Both my original mk2 335 (purchased 1980) and the mk1 I had and indeed the current mk2 I have were all fitted with the dial rear sight and leather piston seal.
The sliding rear sight might be the 333 model....as for ptfe seals,from what I know these are after market types, I have one fitted to a mk2 now and imo its a bit more harsh to shoot compared with leather.
I also have a diana seal which I will replace the ptfe with.
They shoot nice at around 9-10ftlbs.