Bert-Co, which did label type on {Images #2724275 & 2724276}, was the only one of the printers RCA Victor used to have "HIS MASTER'S VOICE" printed below the 4-color Nipper. Looks like label blanks were printed on the West Coast by them and on the East Coast by Keystone - which was listed in some print article as printing label blanks for them.
Are the first two variants of these Color Nipper labels (not just images 414755 and 414755, but also 422053 & 422054) both Indianapolis pressings, just from different times?
The variant {Images #422055 & 422056} was an East Coast pressing, probably from Rockaway, NJ; the label fonts used were prevalent on RCA Victor releases up to their switching to Co-Service Printing of Newark, NJ by later 1955.
A side: Title info in larger typeface, Film title has exclamation point, NEW ORTHOPHONIC HIGH FIDELITY moved to left of spindle hole, matrix number hyphenated as E4-FB- and moved with catalogue number to right of spindle hole, Artist credit in all caps
B side: Title info in larger typeface and has word Rumba after title, Film title has exclamation point, NEW ORTHOPHONIC HIGH FIDELITY moved to left of spindle hole, matrix number hyphenated as E4-FB- and moved with catalogue number to right of spindle hole, Artist credit in all caps
A side: Title and composer info reduced to three lines from four with larger typeface, Mambo in italics, Film title has exclamation point, NEW ORTHOPHONIC HIGH FIDELITY (all caps)
B side: Film title has exclamation point, NEW ORTHOPHONIC HIGH FIDELITY (all caps), Word "The" in "the king of the mambo" has capital T