Heater channel without a defrost port?

[GreyhoundBeetleC2A]

Afteroon VeeDub fans,
Ok, here's a new one on me. I'm putting the fresh air box and hosing back as close to OEM as I can. There was no defrost tubes at all on the driver side, found a few helpful hints here atbout how to replace the missing pieces.
So i drill a 2" hole in the side pillar and look inside, lo and behold, there's NO defrost outlet at the end of the heater channel! I hooked up the heater boxes, there's hot airi coming out the vent, but no defrost outlet at all!
Has anyone ever seen this before? I can modify a piece of PVC I think, replacing heater channels is NOT an option at this point.
I'd appreciate any feed back, btw, mine is a 1974 beetle.

Thanks
Tom