fixbutte - Added original b-side label image - hopefully that’s fills another image gap ! That definitely sounds like Red Foley on the b-side but I can’t make him out on the a-side. I agree that there’s no clear hint of Merle Travis’ guitar.
Here's a YouTube video of group's excellent recording of "Will The Circle Be Unbroken", credited as arranged by the group but actually using the lyrics rewritten by A. P. Carter for the Carter Family in 1935.
As said before, Alton Delmore handles the lead vocal in the verses, and if Merle Travis was there, his contribution is not obvious. Anyway, the record must have been quite successful, and the group was requested to make many more records for King.
Brown's Ferry Four was founded as a mock gospel quartet by the Delmore Brothers, Merle Travis and Grandpa Jones in 1944, when they were all playing for the WLW radio station in Cincinnati, OH (see King 503).
For this recording, the group's first, the information about date, place and lineup is controversial though. Several sources mention a February or March 1946 session at Radio Recorders, Hollywood, CA, with Alton Delmore (lead baritone vocal, guitar), Rabon Delmore (tenor vocal, guitar), Grandpa Jones (baritone vocal), and Merle Travis (bass vocal, guitar). The Delmore Brothers website, however, comes to the conclusion that the session took place at the King Studio in Cincinnati, OH, around January 1946, and that Merle Travis was not present on this session, the bass singer was rather Red Foley and the two guitars were played by the Delmores (based on the matrix numbers and the acetates which read "Cincinnati, Ohio", and the recorded music; Red Foley would definitely provide the bass vocal on some later recordings of Brown's Ferry Four).