Okay, here's what I've been able to gather from these records with regards to the date...
Rutherford mentions that Jehovah's people will be going to heaven to live in everlasting peace. He does NOT mention that they will be living forever on the earth. Therefore, this places these records at a date earlier than 1935.
I also find it interesting that Rutherford tells the listeners about the JWs who are going door to door. The fact that these records are made for radio makes them quite an interesting listen.
As a side note, one of them has quite a bit of damage, making only about half the record audible.