[Arran]

 There is no guessing at all with this, Philco, at least the U.S made Philco sets did not come with RCA phono jacks. I've also arrived at a policy of removing phono, or any other input or output jacks, for radios that did not leave the factory with them. The reason being is that they don't enhance the use of the radio much if at all, and often cause problems because of the crude and amateurish way that most are typically installed. I've seen so much butchery involved with putting those things in that I really don't offer any quarter to them anymore, so when I see one added to a new to me old radio, out it goes and back to original. There are plenty of factory built sets that came with a phono jack, and there are RF modulators for ones that don't.
Regards
Arran