I hadn't heard was that FFL holders can make their own suppressors without filing the form 1. I know this is going to come up in conversation with my Father since he's held an FFL for the last 40 years or so. I'm assuming that FFL holders can't manufacture suppressors for sale, only for personal use right?
The FFL must be a 07/02 also known as a manufacturer's license to some. They can make a silencer without paying the $200 tax but a form 2 must be filed.
If your dad had that kind of FFL he would know that.