  In the second paper of this series, I obtained the twisted BRST systems and
extended physical-state conditions of all twisted open and closed $\hat{c} =
52$ strings. In this paper, I supplement the extended physical-state conditions
with the explicit form of the extended (twisted) Virasoro generators of all
$\hat{c} = 52$ strings, which allows us to discuss the physical spectra of
these systems. Surprisingly, all the $\hat{c}=52$ spectra admit an equivalent
description in terms of generically-unconventional Virasoro generators at
$c=26$. This description strongly supports our prior conjecture that the
$\hat{c}=52$ strings are free of negative-norm states, and moreover shows that
the spectra of some of the simpler cases are equivalent to those of ordinary
untwisted open and closed $c=26$ strings.
