they will be AC and non AC then different brands. putting in your reg will surely give the right ones?
covered about a week ago http://www.golfgtiforum.co.uk/index.php?topic=247919.0
without a/c you need:v-belt 11.5/11.9 x 685mme.g. http://www.eurocarparts.com/ecp/c/Volkswagen_Golf_2.0_1997/p/car-parts/engine-parts/belts-chains-and-tensioners/car-drive-belt/?202440155&1&7ba6f7562303be16f4ef1ccd5c56015104b996f1&000108ribbed belt 6pk892 or 6pk895 will also do if you got 70 or 90A alternator http://www.eurocarparts.com/ecp/c/Volkswagen_Golf_2.0_1997/p/car-parts/engine-parts/belts-chains-and-tensioners/car-drive-belt/?202120015&1&8cb521afcf81edde869498300cdd99f4d29a9d81&000108or 6pk1040 if you got 120A alternator (which usually is on diesels or some high spec with lots of electrical extras)