I cannot really argue with your hypothesis as the facts are not really known either way, but I can offer an alternative.
Open the door... quickly became a massive seller for what was a relatively small and brand new label. The Canadian Revilot release was distributed by London/Decca, however the Quality label had strong ties to MGM, the owner worked for MGM before launching Quality. If LeBaron Taylor decided the record plant/distributor wasn't keeping up with demand, for the record, he may well have swapped U.S. plants/distributors. MGM seem to have used 4/5 different pressing plants throughout the U.S, this would mean there could have been all sorts different imprints of the record. The London/Decca connection and the Quality/MGM connection may also indicate what happened in the UK re London/Stateside. Obviously London (UK) was linked to Decca (UK) which also owned London in the U.S. and Canada. MGM seemed to have ties to EMI in the UK, if you look at Bok To Bach UK issue it has the same "Sold subject etc." as EMI releases of the same period. One things for sure, the Revilot label was a strange one when it came to rights/distribution etc, even in the UK it's product came out on at least 4 different labels, London, Stateside, Polydor, Track.