Slant 4 water pump parts ?

[MIG Wielder]

I have found some new Slant 4 water pump bits, together with some old parts.

I know the old bits are well used because the oil seal is grubby, the bearing is rough and there is an old lower bush.
The new bits are interesting. The bearing is a silky smooth RHP (!) but the water seal is different. It is a 2-part type held together with a plastic cage. Apart from that it is identical to the old one.
I seem to remember that the underside of the impeller has to machined to fit this. And the top half of the seal has then to be glued in.
Is this correct please ?

What type is the latest ( good quality ) water seal supplied please ?

Thanks,
Tony.