To answer your questions:
1. It has a 21Mhz IF. I refer to it as an early 60s set because I recall finding that date code either somewhere on the chassis or in the accompanying documentation. I suppose it could be late 50s; I haven't found _any_ info on this set online barring a similar-looking but not entirely identical picture from a 50s sale brochure (the 21-41):
http://www.tvhistory.tv/1950s-CAN-Fl...-Brochure3.JPG. Someone with an RCC Master Index might be able to pin down an actual year.
I'll have another look and see to confirm or deny. I wouldn't be surprised if there were still 21Mhz IF sets in Canada later than most of the US; we were pretty behind with FM adoption in tube radios too (not all that relevant, I guess) and the manufacturers might well have opted to save some re-design costs by extending the 21Mhz design a bit longer...
3. You're absolutely right; I don't think dot crawl is the term I was looking for. I was reading about other types of noise and how one of them could be mistaken for chroma dots, but the name escapes me. Dot crawl must have been the first thing that latched into my mind.