No, according to the manual, the 72 and 93 both support pass through. Well, the manual says a model 73, but it appears it is referring to the 72 as the manual is for the 33 and 93 as well.

Page 34 - Dubbing to or from a VCR

(right hand column - middle of the page)

To use this camcorder as a recorder (GR-D93/73
only)
1) Perform steps 1 to 3 in “To use this camcorder as a
player”.
2) Set “S/AV INPUT” to “ON”. ( pg. 25, 28)
3) Set “REC MODE” to “SP” or “LP”. ( pg. 25, 26)
4) Insert the recording cassette in this camcorder.
5) Press the Recording Start/Stop Button to engage the
Record-Pause mode. The “ ” indication appears
on the screen.
6) Press the Recording Start/Stop Button to start
recording. The T indication rotates.
7) Press the Recording Start/Stop Button again to stop
recording. The T indication stops rotating.