The statistical odds are higher than you may think!
The statistical odds are probably higher than 1:1000 based on serial number alone. When other factors are considered, the statistical odds may jump to 1:100. If someone can conclusively connect the rifle to Corporal Conover's surviving family and validate Corporal Conover's service record with a little research, the statistical odds go way up! And if Corporal Conover can be connected with an NRA-affiliated shooting club prior to WWI, that would clinch the deal.
J.B.
p.s.,
Lt. John George, author of Shots Fired in Anger, took his .30-'06 caliber scope-sighted Winchester Model 70 to war with him and used it with great effect on Guadalcanal in 1942. Read the book!