Linda
Your assumption is correct, if the type species of a genus is later considered as a junior synonym of a species, the correct name for
the species is the senior synonym.
The well known Sowerby's were all George the 1st 1778-1854, the 2nd 1812-84 and the 3rd 1843-1921. Souverbie S.M, left his collection
to the Bordeaux Museum, totally different family.
Kev