NO ALLIUMIUM BAFFLES IN MY HEATER BOXES?

Just pulled my heater boxes off my '72 standard beetle and they dont seem to have the baffles inside them like the ones of my old '69 beetle has, when did they stop putting them in? And do they work as well as the older models?
Cheers SAS:duh:tree:beer:tree:beer:tree

Some of the cheap Brazilian replacement boxes don't have baffles in them, but also late Beetles, '74 and on don't have them either??.
And yes they don't work as well as the older ones.

Thanks Dave