Took the pic to a shadowy friend who claims to know more about the JFK assassination than Oliver Stone, who is a CIA-type guy and photo expert. He did the blow-up analysis, plus enhancement, to check out the name tags. There are five in view. The logo suggests SAM (not IBM) convention. The wallpaper and decor are in keeping with the Morrison Hotel in Chicago. Checking the relative age-appearance of guys like John Braun, who was born in 1896, and judging by other photos snapped during his lifetime, he looks to be early 50s. Same applies to Sid Lorraine, who was born in 1905.Therefore, this pic was probably snapped somewhere between 1952-56. This is also in keeping with the eye-glasses and necktie styles.
The pen in Tarbell's left breast pocket is an Easterbrook. The cigarette in Okito's left hand is unfiltered and an "L" shows on the cigarette paper (though very faint), suggesting that he was smoking a Camel.
The fourth figure between Braun and Lorraine was not there when the pic was snapped. This is a doctored pic because the textures and other details do not match. The position of his right eye is not focussed on the camera man.
Oddly enough, in candid shots like this, Allerton always had a furtive look, as though he was being arraigned.
My expert pointed out that none of the posers were looking at the camera man. The shadow of the chandelier cues the direction the pic was shot.
The resolution of the camera also suggested that this was done with a quality, press-type camera.
The mystery-man to the far right, the tallest man of the group, was not part of the primary group.
Otherwise everyone else is identified.
Who "doctored" this pic is the real mystery.