Phonozoic dates this type of Recordisc the Type 2C to around 1948.
I've come across a few of these. They're always great. It begins with "This is the first radio program over GTS, brought to you by the courtesy of ___ downtown supply..." Strangely the DJ claims to be operating on 1350 AM at 2,000 watts. On the B-side they break up giggling and it seems like less of a pro operation. The DJ is a more confident and practiced than most home recordings. I find it possible that this is a recording of a former WGTS-AM or KGTS-AM. It could also be a pirate station, or faux station at a radio school. He even clearly states the transmitter took 20 months to build, indicating some hands on experience beyond the mic. His engineer 'Mr. Carnell' is going off to study radio. This one remains arcane and a bit apocryphal.