UPDATED WITH MORE DISCOVERIES!
Welcome to another masterpost where you get information that exists nowhere else! Today we are going to tackle a murky subject with lots of misinformation: vintage Godzilla "radio spots," which is for some reason the preferred industry name for radio ads or commercials.
I don't need to tell you, but back in the day, studios and/or licensing companies would prepare specially-made, official radio commercials (as well as television ads) for many of their films, because radio was one of the best places for promotion. These were (usually) free to the promoter, because after all, they helped everyone involved.
The best way to know what was available is to read the vintage pressbooks. All pressbooks for the films we are going to discuss are available on this blog, so I will place links to those posts so you can see them for yourselves, if you so desire. As you will see shortly, there was no uniformity to the media that was used, and sometimes the available literature didn't even specify the details.
So? How many Godzilla films have them, then? Well, the short answer is: twelve. Probably. Hang tight, because here we go:
1) KING OF THE MONSTERS (Godzilla Releasing Co./TRANS-WORLD) A 12-inch 33&1/3 record of 5 spots [first made available on this very blog, dear readers!] was "created by Terry Turner and Don Thompson" according to the pressbook. The book only says they were "available," and doesn't specify the media involved. Only a few months ago, it came to light that these were also offered on a (probably 10-inch) 78 from a kind soul who posted them to YouTube, making these a rare example of spots available in two formats! You can see the KOTM pressbook here, and download the radio ads (and even see the video for the 78 version, which I believe are completely identical) at this post!
2) GIGANTIS THE FIRE MONSTER (Warner Bros./Thaddeus Suski Productions) This record has only come up for sale a couple of times in the last twenty+ years, and apparently the buyers have no intention of sharing its contents, preferring instead to simply hoard it away somewhere. As the pressbook tells us, the record contains "one 1-minute and three 20-second radio spot announcements...taken directly from the soundtrack of the picture." This was a 10-inch, 33&1/3 rpm one-sided disc (you can see the back had a neat textured pattern). You can read the pressbook in this post. This film was released in many places in a double-feature with the dreadful TEENAGERS FROM OUTER SPACE, and the last track on the record is actually for that double-bill.
UPDATE: As kind reader Ultrase7en pointed out to me, two of the ads are actually played in the commentary track of the 2007 Classic Media DVD release of the film, and here they are:
GIGANTIS THE FIRE MONSTER Radio Spots (x2)
3) KING KONG vs. GODZILLA (Universal/National Screen Service) This is an unusual entry, because we are going to discuss two different records! The official disc of radio spots was issued as a 7-inch 45 rpm record on red translucent vinyl (also unique in this list!). There are five ads, although the pressbook ("Showman's Manual") merely says ads were "in all the usual 60, 30, and 10 second lengths." What's most unusual here is that a second record was actually available, and this was an in-theatre one: