[Mark N]

In the USA, the RCA PK-series cameras were considered their "professional line," down a step or two from the "broadcast" cameras, which had TK- designations.
For example, the PK-630 was a "professional" 3-tube studio camera of early 1970s vintage, while its "broadcast" counterpart was the TK-44A. The "professional" line was less expensive, but I don't think it was a very big seller. The professional cameras were designed in California, and the broadcast cameras in Camden, New Jersey. No parts were interchangeable.

That said, I don't personally know of anyone collecting them. I paid about $150 several years ago for a TK-76, and I've seen some other cameras of lesser fame go for less than $100.