Since Southwick ("Made in the USA since 1929") describe themselves as "synonymous with authentic American style, natural shoulder comfort, quality, and fine fabrics..." , it may be safe to assume that the herringbone tweed & the other without fabric content labels are also 100% wool.
The best way to be sure is to contact them & ask if they have made any in a wool blend & if so which styles/types. https://www.southwick.com/home
"It's not what you don't know that gets you into trouble, it's what you know for sure that just ain't so." —
