Yes, but during the mid 1950s Hubbard said there were not other thetans in the body.
He had written about "entities" in 1952 but didn't think they, and their "track," were important.
Only during his post-Southern Africa nervous breakdown (1967) did he start seeing "Body Thetans" and regard them as a problem, and it wasn't until his second nervous breakdown in 1978 (after the FBI raids) that he saw the universe as "crawling" with "fleas" as he called them.
Hubbard's promise of true "OT" in a few years was not happening, so he needed to invent an explanation, which was that everyone on Earth was in a lot worse shape than was originally thought.
It was a bottomless pit as each failure was followed by a grimmer and grimmer "explanation."
From the Incredible String Band's I Looked up album of 1970.
At that time I don't think Robin Williamson would have done OT 3 yet,
and there was not yet any "NOTs" with its "fleas,"
so that dismal darkness would not have yet had its influence.