The first thing to do is have someone who is familiar with Civil War clothing and fabric to check the quilt to assure that the dyes, construction, and style of sewing are of that period. In the early part of the Civil War both the North and South had blue uniforms. As the war progressed the North stayed with the blue and was made of wool. The South also used wool as well as home made uniforms and were colored using dye made from butternuts which account for the fact that the South was more lax in their style and color of uniforms. Most generally the higher officers had their uniforms made by tailors and some of the better to do common soldier had the gray. that is why you see such a mix of clothing in the southern ranks.