The only other state of affairs that I can envision is the fact that it may be a normal Model 70 barrel and motion that has a substitution XTR stock. This can be unlikely while...I suspect that it's as you explain, an unmarked XTR. The bottom window is closed through https://ricardogjllm.pages10.com/a-review-of-winchester-model-70-xtr-featherweight-value-62527666