He wanted to know if left and right are different, and what it may have come from. The length mayhelp with teh second part.

Dave, WB small Salisbury are the same axles as a fine spline banjo (as it is just a disguised banjo). There is another type of axle too, but no applicable to commercials: HZ-WB disc brake. These are shorter and have a smaller flange diameter, plus longer wheel studs.