If I were going to the trouble to make a jacket out of boucle, I would serge or zig zag the raw edges of each pattern piece after I had cut them out. Just my opinion.

I just finished a boucle/Matka-type jac (see Gallery). I would strongly suggest finishing the raw edges before constructing the garment. Serging is best (a three-thread overlock will do and will be less bulky than four-thread), but zig-zag will work if you don't have a serger. Fray check can stain and will dry sorta "crispy" feeling, to say nothing of the cost. If the jac is unlined, you may consider a Hong-Kong finish on the seams, a look I really like, but if it has a lot of seamlines, this takes time, and you could have show-through. If you do a Hong-Kong finish, do a test sample first to see. I made an outer-wear boucle jacket also and completely underlined it with a knit iron-on interfacing, but primarily to stabilize the fabric b/c it wanted to stretch a lot. It also made it warmer, but didn't address the fraying issue, as I always trim interfacing at the stitching line to elimate bulk.

Just my humble opinion!

Mary L