Model 12 Trence Gun Magazine Tube Help Needed

I bought my Model 12 Trench Gun with a commercial magazine tube on it, and wanted to replace it with the correct trench gun magazine tube. I just picked this up based on it having just the two holes in the front and not having four holes with the larger holes for the pin found on commercial tubes I have never handled a magazine tube for the Trench Gun separately (I've had a couple of commercial ones), and I am looking for opinions on this one. It has just the two small holes for the magazine plug, no holes for the pin. However, it seems a bit short, although it falls within the measurements from Poyer's "US Winchester Trench and Riot Guns" which say the length should be 17 inches, but examination of legitimate tubes show the length varies from16.5 to 17.2 inches, with this one coming it at just over 16.5 inches. Outside diameter is on the small side but still within parameters in Poyer, and a 12 gauge brass shell easily fits into the tube. A couple of other things. The stop lug on the commercial tube is missing from the two-hole tube, and although they both have action slide recoil springs stamped with "12", the collar on the tube is different, with the commercial tube being a solid press fit, while the collar on the two-hole tube has three recessed lugs holding it in place.
Here are some pictures to show the differences.
The first picture of the tubes shows the commercial tube on top, the two-hole tube on the bottom. The pictures will maintain this relationship. The commercial tube is 17 inches long.
The second picture is of the front showing the two-holes in the bottom tube
The third picture shows the stop lug on the commercial tube, none on the two-hole tube.
The fourth picture shows the collar and the action slide recoil springs.
Any help with this is appreciated.

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Original post should say Model 12 Trench (not Trence) Gun Magazine Tube Help Needed.

The first thing you need to do is take Poyers book and throw it in the trash.
He merely reported on things he saw at shows, nothing in there says what is correct.

Are you sure one of those is not off a model 97?

Both tubes have the pair of ribs and the arrow for alignment. Unfortunately I don't have a book on the Model 97 but having looked on the internet both of these look like a M12 tube. I don't think the M97 tube has the pair of ribs but I'm not sure. Differences between the two tubes in this post are the stop lug and the collar (other than the length and holes on the end).

Alright, looking at the tubes closer I have discovered that the "pair" of ribs are actually three ribs equal distant around the tube.

1. Took the tubes to my gunsmith friend, he confirmed that the shorter one had been cut-down and the collar had been replaced.
2. If Poyer is no good, then what book is? I'm aware that many of his books have short-comings, but where else is there a book on the details of the Winchester Trench Guns? I have the US TM, Canfield, and a 1957 book on take-down and assembly. None of them provide the detail that Poyer does, and even if there are mistakes, I would hope someone would point them out.

Poyer quotes stats on incorrect guns, how does that help?

What stats are incorrect? Where do you find the information? Every book has mistakes and errors, but usually you can find other books that let you find those errors, but what else is there to Poyer? For example, he says the magazine tube is 17 inches long. That corresponds to the actual measured length, but where else can you find that dimension?
It's almost a mantra to read the books before buying the firearm, so where are these books on the Winchester Trench Guns?