Herman Miller Group chair aluminium lounge date ??  

A picture would probably help.
but does it have a 4 star base, or a 5 star base (4 legs or 5 legs)?
carry on.

HERMAN MILLER GROUP CHAIR ALUMINUM LOUNGE date ??
Yes it is a 4 leg base , no arms , ill try and get a pic up , yet they are so mint Im unsure its 58 , no other markings except the Herman miller patent pending

these are the chairs
these are the chairs

ok these are the chairs
ok these are the chairs

It's vinyl
That's vinyl, not leather.

Could the base be made by Vitra?
Yep, that looks like vinyl. They're older examples.

cool , thank you very much ,...
cool , thank you very much , with the patent pending , would that be on the first run in 1958 ??? or did the patent take a while for the # to be applied in production .... late 60's ?..... I know I saw one from the early 70s and it had a patent # . on it . They just seem to have very little wear, so i did not think they were 50+ years old Thanks again .

ohh whats the best way to...
ohh whats the best way to care for the vinyl ?? armor all ?? or some cleaner without any silicone oils, petroleum solvents or gloss agents ? Thanks for your insight .

Care and cleaning
here:
http://www.naugahyde.com/cleaning.html

ah, i was thinking about those.....
did you pay retail, or make an offer to get both? 😉
never mind--they're great chairs!