Now i'm sure some of you old farts(like me) can remember when water pumps had grease nipples on them.

Ive just bought a new water pump for my mates 2.5 na and the water pump has a hole where I assume the grease nipple used to go.
Is there ant reason I could not tap a thread into the hole and fit a grease nipple?

Usually the hole if on the underside of the pump is a drain, if it’s a very early pump with a nipple then that should already be fitted,
Unless it’s very old stock water pumps where one of the first parts to become unserviceable and thrown in the bin when at end of life,