No, but on British stuff from that time, it helps, but is by no means a given.
The printers won't have been lazy, as they removed the RKO logo, and put Disney onto it. 6000 + numbers on Staffords were very late 40's, they changed in 1950, and started again, I have an On the Town, released in 1950 with a number 17 on it. Staffords had several letters on their numbers, C for Columbia, BL for British Lion, not sure what the A was for.. and these again had different numbers.
Anyway, from what I know, it's a late 40's rerelease, but what do I know, I haven't wrote a book, just some graffiti on the toilet wall... ;-)