That's supported by various Toho print materials from the early 1960s, including a poster and the entry from Toho Films 1963 (spoilers in the latter's synopsis).
The site listing also gives "Toho International (1975)" as the film's U.S. distributor (I'm aware that the erroneous title and distributor information is from Galbraith's Toho book). In fact, it had already been in television syndication at that point, however, going back to October '63 or early 1964. Note that this is the same package that The Secret of the Telegian was available in; that film's U.S. release ends with a logo for "Westhampton Film Corporation," so perhaps Desilu just handled the business of syndication itself.
Source: Heffernan, Kevin. Ghouls, Gimmicks, and Gold: Horror Films and the American Movie Business, 1953-1968. Duke University Press, 2004, p. 237.
I've never seen any syndication prints of Attack Squadron and thus cannot comment on the runtime, but at least Toho's international version (dubbed by William Ross with a pre-Frontier Enterprises group) is uncut. It's probably safe to conclude that the U.S. television version was simply the Toho export version, as was the case with Westhampton's syndicated version of Telegian.
