These “Vintage” Heating channels are different from the regular standard versions. The big difference is in the shape at the front heating opening. 

This runs nicely round here and is shaped as original. The openings on the standard channel have a rectangular bulge, which is not correct for early beetles. 

There are 2 versions of these 'Vintage heater channels, 1 with and 1 without holes for the heater. So both have no heat conduction tube internally, something that was only applied later by vw.