Nah dude, check the thread I linked to above, where I switched the speakers around between top and bottom, and they sounded noticeably different (and the cab was elevated off the floor
like so). And I never understand when people say they prefer to mic the top speakers even with a straight cab, where theoretically there should be no difference between top and bottom (unless of course the best sounding speaker happens to be in the top row). And by extension, I find it hard to believe the bottom speakers in a slant cab would be boomier sounding than any speaker in a straight cab, but that I don't have enough experience with to say for certain (seems unlikely to me though).