I had the same thought some time ago, but I have no idea where the telephone transfer ended up after the magnetic stereo prints were made. I’m not sure if RCA immediately junked their copy or if it ended up in somebody else’s hands after the company went under, but whatever the case, and until someone pops out of nowhere with those RCA mag reels, it seems that copy was sadly lost to time as well.
I’m telling you, the soundtrack to this film could not catch a break.