Maybe, maybe not. Probably the fastest way to check is to draw in 1.5 cm seam allowances on neck edge and collar or band. Measure the seam lengths (be sure to subtract the shoulder seam allowances, etc.). If the neckline seam length is equal to the band, then the seam allowances are there already.
In general, US-made home sewing patterns (Vogue, Butterick, McCalls, Simplicity, KwikSew, Stretch and Sew, etc.) have seam allowance included. Jalie and McPhee Workshops (Canada) patterns include seam allowance. Burda patterns in the packages have seam allowance already added since the early 90's. Burda patterns before that did not, and I believe the Burda magazine patterns still need to have SA added, but I'm not sure -- haven't used them in ages. Some Japanese patterns have SA, others need it added.
Sorry I can't be of great help on this -- I prefer to make my own patterns, and usually wind up using the same seam allowances industry does instead of the home sewing 5/8"/1.5cm.
Most pattern companies do have a customer service email and phone number on their website -- that's probably the most direct way to get your questions answered.
50 years of sewing
· 1 decade ago