Dash tops

Ok when I was at the breakers the other day I managed to pick up a.really good condition dash top however I've noticed that it is different to mine. It has small vents for the heater ducts when my original has larger vents. Does anyone know why they are different? My original dash has a big chunk missing from it.
I've also now noticed that my bottom dash is rotten so will need to try and source one of these now.

Norrie

Only reason was defrost more or the screen.

Ok so there's no reason I can't fit the earlier style dash then?

Norrie

As long as the fixing holes line up.