  Based on the postulate that photon propagation is governed by a dynamically
broken SU(2) gauge symmetry (scale $\sim 10^{-4} $eV) we make predictions for
temperature offsets due to a low-temperature (a few times the present CMB
temperature) spectral anomaly at low frequencies. Temperature offsets are
extracted from least-square fits of the anomalous black-body spectra to their
conventional counterparts. We discuss statistical errors, compare our results
with those obtained from calibration data of the FIRAS instrument, and point
out that our predicted offsets are screened by experimental errors given the
frequency range used by FIRAS to perform their spectral fits. We also make
contact with the WMAP observation by blueshifting their frequency bands.
Although our results hint towards a strong dynamical component in the CMB
dipole and an explanation of low-$l$ suppression it is important in view of its
particle-physics implications that the above postulate be verified/falsified by
an independent low-temperature black-body precision experiment.
