I guess you stumped everyone with this question Pope. My gut says you're correct, but I don't hunt those zones, so I cannot say for sure.
We do know that the USFS lands have fewer deer for exactly the reason you suggested. 100% canopy closure means no browse, so the deer in those areas will not use those closed canopy conifer areas much, except for traveling to where more food or deer live. They may live on the edges though, above and around those alder flats - but that is a guess. The vast amount of geographical area involved in these similar aged forests in the Cascades, all being essentially in full closure, caused a reduction in deer populations many years ago as the browse died out. Without some event that resets the clock and allows new browse to form, the population will stay relatively stable at much lower numbers than occur elsewhere where logging or fires have occurred. That seems to be the primary reason why deer hunter numbers are low in the USFS lands and why hunter success is correspondingly low.
Search Google Earth carefully for any pockets or openings that suggest something other than closed canopy conifer is present and you've likely found a good spot to scout a bit. I'm not sure exactly where you go, but if you have any areas similar to those on the western flanks of Mt. Adams, where the USFS has done multiple thinnings over a relatively large area, (or a fairly new burn), those types of spots might be the best location to devote your efforts.

(and it's probably not worth that much).
G.