What Edward said is 100% right, although basing upon the year (I understand - the production year) I can be nearly 100% sure that the truck is 352-03, the engine is Perkins and water pump has the number U5MW0167 which is the Perkins No, so you should be able to get it anywhere.
Original Perkins water pump it's a cost of ~ 130Euro, replacement ~60-80 Euro.
in forklifts, the complete serial number is more likely to get better opinions than is the year of first sale. can you give us this truck's serial number and type of fuel (diesel? LPG? petrol?)