I worked with Butterick 4138 which had front and back facings.
- Reinforce inner corner of front pivoting at small circle. Clip to small circle.
In the past I have not wanted to clip the fabric after reinforcing (I was scared to cut into the fabric), thus creating a problem in getting the collar to fit properly. So do clip; the line of reinforcement stitches will keep the fabric from stretching out of place or even tearing further than the clip.
2. Stitch fronts to back section together, and then stay stitch the neck edge.
3. Stitch under collar and upper collar together on sides and upper edge. Trim all edges and cut points.
4. Turn collar; press (taking the turn of cloth into consideration); baste neck edge of collar together. Pin collar to neck edge of jacket pivoting at small circle. Stitch.
5. Reinforce front facing just as done on jacket front. Clipping both front facings to small circle. Stitch back to front facings.
6. Pin and stitch facings to jacket right sides together. Trim seams, turn and press.
I hope this makes sense and helps you out...