Pattern includes 3 two sided pages (1 has instructions) and 2 single sided pages, in original mailer from The American Home Pattern Department in Forest Hills, NY.
Mailer meter is not dated, but the H3 N.P.M. National Postal Meter mark is circa 1940s.
More vintage sewing:
https://buffalogal.ecrater.com/c/2376079/vintage-sewing?&perpage=80
kmm1