The cut you’re thinking of is not the general release, which received a much wider, nationwide distribution, but a slightly modified recut of the original roadshow version which, yes, did bare the RKO logo before the program started to indicate the company’s then-recent distribution takeover; nothing else was changed. In a perfect world finding a copy of this would be ideal, but the problem is that even if you were able to track it down, it would not contain even a mono downmix of the original soundtrack, let alone the original stereophonic mix, because both the footage and soundtrack ran on completely separate reels of 35mm nitrate film. Tracking down the original nitrate soundtrack has been a fruitless effort, too, as the last one that survived by 1955 no longer exists today. Just a 4-track magnetic copy of it, which was used for the 1956, 1963, and 1969 releases.
Considering the original stems are long lost, I truly do believe that the best bet right now is to get a clean capture of the mag stereo soundtrack and the 80min RKO cut (from a reprint if those are still around) that contains some of the missing Taylor audio. That combined with an uncensored IB Tech print, along with the interstitial and intermission footage from the Blu-ray, would yield the most complete version of this movie that uses as many of the original elements as possible.