Engine/Transmission (1998.5 - 2002) Water Pump Questions ?

[Turbo Terry]

Replaced my stock water pump the other day. Notice two things different. First the new gasket is round instead of squared and second on the inside of the impellers there is a cone shape disc where on the stock one there was just the impellers and no disc but the impellers went up against a disc. No leaks and seems to work okay but has anybody elas noticed this?