Would a Mk4 alternator fit a Mk1?

Alternator came off a mk4 golf 1.8 gti and I've got it lying around doing nothing since I got rid of the mk4 and was hoping to put it to better use as it's relatively new. Would it be a simple direct replacement onto my mk1 and work fine or will it not work or do I need to change pulleys etc?? Thanks in advance guys ! FYI my mk1 is a 1.8 gti also 

I may be wrong but wouldn't the Mk 4  alternator run a "ribbed" belt whereas the Mk 1's run a "V" belt. This would be the same for the Water Pump and Crank pulleys .