grease inside a lens

Just received this G-Claron 355 barrel version.
it looked a bit dirt so I disassembled it and found what looked like black grease residue around/over the inner retaining rings.
residue of it was found also on the two meniscii and on the inside of the metal casing.
I had it all clean, dry and reassembled.
it looks nice, but I am not sure if I should leave it this way or reapply a gentle quantity of lube to the inner threads of the retainers.
what's the best practice?


https://i.imgur.com/zc3kKiG.jpg

https://i.imgur.com/MvBvm0b.jpg