in the second pic,there is evidence of grease in front of the old piston seal,as you can see the imprint of the transfer port.glad you have noticed that and decided to change it
in the last pic,it looks like you have dark moly grease on the out side of the piston seal,rather than a clear grease ?
the clear grease i use on piston seals,O rings,guide, pretty much any rubber/ delrin to metal moving parts. i am sure i have read somewhere that its to do with the minerals in the each grease,hence why one is for metal to metal moving parts,and t'other is for seals.
i think its to do