if you visit the American Quilters Society they Certify quilt appraisers & have a list on their site with certified appraisers organized by state- maybe you could contact an appraiser & have them looked at- or check with a local guild & see if they have anyone who specializes in 40's /vintage quilts-
location matters ---and prices vary greatly across the country. you will get the best answer from someone who can actually look at the quilt & give it a fair appraisal.