Her Nibs sings with Georgia Gibbs was on the label because she is overdubing the vocal like a duet Her nickname is"Her Nibs Miss Gibbs".Side A made #18 on the BB pop chart 1/13/51.
A side or not, it's no wonder "Once" was not the popular side, it's so "old-fashioned" even for '51. The radio jocks (announcers) picked the hep side to play and in these days every record store had booths so you could try before you buy and the record cats reported to BB and others what people were asking for. Glen Gray had the '35 hit of "Out In The Cold", went to #4 BB.
There are two things I would like to add to the discussion, First 78s were out of favor in the U.S. by 1957 and production by around '58. The 45 was king from '56 on. Also, in the last years of the 78 most were made of an unbreakable plastic and improved fidelity but the heavy-handed (or should I say heavy- armed) players were no match for the new high fidelity players.