The Very First Columbia 33RPM "Singles"

Anyone out there have any information on the titles of the first two Columbia 33 RPM singles, released in the 7-inch format circa 1948? The oldest one I have is catalog number 1-103 but I also have what seems to be two test pressings with blank red labels and earlier master numbers (and I did compare them to my copy of 1-103 to verify that they were Columbia master numbers) - these are also 33 RPM 7-inch singles. There is no other information on the records except for the song titles someone had handwritten on the edge of the labels (and I don't have access to them at the present so I can't state what they are - one of the records sounded like it could be Xavier Cugat and his orchestra). Thanks for any information, anyone!

I have some interesting related information. Most of the Latin American countries never adopted the 45. All of their singles are on 7" 33.

Yeah, I've got a record from Bolivia which fits that bill (then again, it might be a 45 with a small hole...I'd have to check). But I'm certain my mystery discs were US pressings with the "ZRP" master numbers they were using at the time of the introduction of the 33 single. When I found them (in an antique mall among a varied selection of other 45's) I thought that maybe they were some budget cover-version label. If it wasn't for the hand-written titles on the labels (ooohhh...does that wreck their value?!) I'd have almost guessed they were one of those anonymous "party records" like you'd find on 78. But they're not - all four songs between the two records are straightforward Contemporary tunes.