From: Thomas Jones-Low

> 	From what I recall, one variation of the coyns sold were the
> sheets that were included in AR3, but sold as a separate items. (i.e
> thick paper stock/cardboard which you can punch out the individual
> coyns, with a few sheets of instructions).

http://www.sjgames.com/gurps/traveller/alienraces3/#coyns is likely what you're thinking of.