First, a big Ukulelia thankee to Jim Tranquada, who writes:
"That's Noah Allinkov on steel, joined by Clyde Jewett, Edward Hahn, and Jack Mesquit (apart from Noah, I'm not sure who is who). They were regulars on KHJ during the summer and fall of 1927; I suspect the photo was taken in the KHJ studio. They played a wide range of standards, in addition to what was referred to as "Hawaiian love songs.""
Also, in the comments section of the post (hey, check out the commenting feature, dear readers!), one Jack writes:
"The guitar is a parlor size, perhaps a Martin 0-18 or 00-18. I think the next is a Gibson Mandocello."Thanks to both Jim and Jack. I've also found this thread on The Steel Guitar Forum. Anyone else have any intell?
UPDATE: Al Dodge informs us that the mandocello is indeed a Gibson Mandocello, but with a National tailpiece. And the steel geetar is a Style 2 National Tricone. And in case you're wondering (as I was) what the diff is between a mandola and a mandocello, "Beachless" Bob Armstrong 'splained to us that the mandolin, mandola, and mandocello are the analogues of the violin, viola, and cello, respectively.