The more I look at existing and available original Pacific catalogs, the more it looks like the company opened for business before 1928
It appears as if they got patents on sights and for a loading press in 1928, but as the catalog numbers seem to reflect annual (or nearly annual) revisions to the offerings, with Catalog 9 in 1933 and Catalog 10 in 1934, and I see a catalog number Fifteen dated 1937 -- I think early 1920's is more plausible.
What source do you have stating that Pacific Gun Sight Company started life in 1928?
Still pondering...
