Is these them :
http://www.ebay.co.uk/itm/NWT-Speedo...AOSwEK9W~z5 Q ?
They are 1970's style 3" nylon Speedos. This was my first pair of Speedos in a size 32", but I soon progressed to a 2" style and then from nylon to Lycra.
$30US + postage (postage to UK is $23US) seems prohibitively expensive unless you want this swim brief for historic collection reasons.
I think the shininess that you are seeking comes from wet look Lycra, polyamide that used to be used in waterpolo suits and from PU Lycra.