If it is the chin spoiler below the front bumper, then I have one on my Cab. It just clips into place and is available from Awesome at about ?75.
http://www.awesome-gti.co.uk/mk1golfprices.htmlIt is a straight forward fit - 2 bolts either side and a couple of clips along the front.
My car is lowered on 14's noe so the spoiler sits so low it catches, to the extent it got ripped off the other day. Its repaired and back on now, but be warned!
You should be able to make it out in the pic below (pre-lowering/14" alloy days)