Lemme go for the quick win here before I hit a couple more posts later.
I'm well aware of a pistol belt. But that's not what I'm talking about, and I suspect not what the Sayers/Weitzman is getting at.
I had an uncle who lived about a mile and a half away when I was a kid. He had a security business and was, for a time, a reserve police officer IIRC. Had the belt with cartridge loops and the whole nine yards: revolver, cuffs, nightstick, flashlight, pouch for a speed loader, the whole shebang. A belt can be pretty cool when you're 10, if it's decorated with the right accessories. It was thick, it was wide, it was surprisingly stiff for a belt. It was heavy. Heavy for a belt, just by itself. All that was because of all the cop bling it had to support. It seemed to do its job pretty well. But I wouldn't want to use it as a sling.
I'm sure you know, if maybe others don't, that one of the prime purposes of a sling is to help the shooter hold a rifle steady while aiming. This function generally involves the shooter wrapping the sling around his or her non-dominant forearm to take up slack and help keep the sling taut. Something as wide and stiff as one of those bandolier gunbelts is going to be too stiff, heavy and bulky to be very useful as a rifle sling. I've seen a number of what you could call leather "bandolier slings'" over the years though they don't seem to be too popular. And everyone of these leather slings that I could call a "bandolier sling" looks something like this:
where the bandolier piece is separate from the rest of the sling, relatively short, and wider than the sling proper. Connected to the sling with metal loops or buckles or just a pair of holes that the sling slides through, like in the example I posted. The idea is that the semi-fixed bandolier piece can be moved to keep it out of the way when you need to wrap it around your arm to assume a proper shooting position. While the pad on the CE139 "sling" doesn't have loops, it does give the sling the kind of silhouette one would expect from a "bandolier type sling."
where the bandolier piece is separate from the rest of the sling,
It appears to be riveted to the sling....
This is what Weitzman was describing..... A thick leather brownish black BANDOLIER type sling.....