When I see a DOT tire rule, I take that to mean both front and rear. Now, at a lot of the street car shootouts I've raced in, they always allow a non-DOT front tire to run. Never seen anyone DQ'd for having ET Fronts.

CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax