I wish they'd done the George Wallace version. Even that used a lot of footage from the earlier Commando Cody, but this newer one with Judd Holdren is mostly made up of stock footage from the other two serials.
Actually, you may be thinking of Zombies of the Stratosphere. This is the proposed TV series that was released to theaters when the networks passed on it. There are no cliffhangers. Each episode is complete but the series needs to be watched in order. It's like an early silent serial in that fashion. It had stock footage but not so much from the Rocketman serials.
There's four Commando Cody/Rocketman serials:
King of the Rocketmen from 1949 with Tris Coffin as the hero Jeff King.
Radar Men From The Moon with George Wallace as Commando Cody
Zombies of the Stratosphere with Judd Holdren as Larry Martin and Leonard Nimoy
Commando Cody, Sky Marshal of the Universe also with Judd Holdren this time as Cody wearing a domino mask.
Commando Cody was intended as a TV show, The first three episodes were shot in 1952 as a follow-up to Radar Men From The Moon (actually, in some ways Cody's origin story). However, they made Holdren wear the mask in case he proved difficult and they wanted to replace him (a la Clayton Moore on The Lone Ranger being replaced by John Hart for a time). The networks passed on the show so Republic decided to just show nine more episodes and release them all to theaters. Shooting was in early 1953. The fact that the show wasn't picked up and the remaining episodes were shot later is one of the reasons William Schallert is replaced. He's only in the first three episodes, which do seem to close the story. He then gets replaced by Richard Crane in episode four!
The 12 episodes, each one complete by themselves, were offered to theaters. Interestingly, Holdren doesn't play Cody in Zombies of the Stratosphere, but a character named Larry Martin, nor does he wear the mask. It's also worth noting that Commando Cody's episodes are all 30 minutes while all other Republic serials at the time had a 20 minute first episode and 13 minutes for the remaining chapters.
To make things even more confusing, Aline Towne plays the same character in Radar Men and Commando Cody, but goes by a different name in Zombies even though she's basically the same character! Meantime, Wilson Wood takes on the sidekick mantle, basically playing the character originally played by William Bakewell and William Shcallert!