jonwvara 

Thanks, jeirvine, but those appear to be regular five-speed bodies. Both the regular 6 speed and the narrow-spaced Ultra 6 bodies have an "overhang," where the male-threaded part of the body extends a few mm beyond the faceplate. In the five speeds, the faceplate is flush with the body.

"Faceplate" probably isn't the right word, but that's the best description I can think of. I don't really know much about freewheels other than how to disassemble and reassemble Suntour Perfects to meet my requirements--they seem to be bombproof, and I have them on all of my bikes except the lone one with a cassette hub.)