I have a 97 Range Rover 2.5DSE. After having a diagnostic check it needs a new fuel injection pump. I have the chance of a second hand one in good condition from a 96/97 Range Rover 2.5 diesel. WhatI want to know is does the numbers on the fuel pump itself have to be exactly the same? About half of the numbers domatch. Would be grateful for any help on this.

Thank you.