Need help id'ing Scope Booster

I'm currently making notes on some old scopes that I will be putting up for auction, with one being a Winchester A5 USMC Scout Sniper Scope. However, I have one Winchester A5 that was fitted with a power booster a long time ago that I need help to properly identify. The booster is about 3 & 3/4 inches long as shown in the picture, it is marked 2170 preceeding the 8X stamp at the small end . As you can see in the picture it has knurling on both ends, and the objective lens adjusting part is numbered from 0-3. This booster appears to be different in several respects from the four that are pictured near the end of Stroebel's book about scopes. However, of all the specifications given on all of those shown and described, I thnk it might be the "Targeteer Senior 10X, 12X, 15X" which also notes on the following two separate lines below the model designation, "Scope Lyman 438, 5A, Winchester A5, 8X," Any help is appreciated: