Yes, that is a fact because the man Tommy Shaw had replaced was John "J.C." Curulewski (1950-88). J.C. played guitar and keyboards on all four of Styx's Wooden Nickel albums and their first A&M release, Equinox. J.C. quit shortly after the release of Equinox, before the band was to tour in support of it. That was when Tommy joined.
~Ben