I don't think these tracks had their own release. Musically, they are not that exciting, had been conceived as a reunion with Leo Parker, Dexter's room-mate from the Eckstine days, but Parker died shortly before the session. To me it always sounded a bit tinged with the sadness about Leo's passing.
The main reason for me getting the box were these tracks anyway, beacuse I knew they'd never be made available outside the box.
Well, until now ...
The LT series LP sounded much worse than any of the later Connoisseur or other CD reissues of the material that I have compared. I replaced all of them, and I had about two thirds of the series on LP.