I have a Model 70 XTR Sporter in 6.5x55 with the box made in 1985 (G1,734XXX). I cannot find any info or value on it. It still has parts of the hang tags & appears to be on fired. It is not a feather weight which is listed in the Blue Book.
The only one sold on auction here was the featherlight and that caliber appears to be made only one or two years= 85-86? It sold a little over $1200 with box.
The Featherweight is the only thing that I can find mention of in any book or on the internet.
Apparently made for the European market. Google "Winchester XTR70 6.5x55" and you will find some discussion on it.