You haven't come across one because there isn't one. If you aren't sure post a picture, brand, model, etc and someone will confirm. Still iffy, email HQ, they are amazingly quick to respond. Here is the rule,
3.F.1.a General Driver's Seat Regs. Driver's seatback must reach above middle of helmet or higher. One-piece, purpose-built racing seats with properly located, factory-provided shoulder-harness holes are mandatory. Molded plastic seats of ABS or similar material are not allowed. All seats must be very securely mounted to the floor or cage to avoid separation during a crash. All seatbacks must be restrained against rearward failure.
Team Glue Sticks
00 Firebird, 02 X-Type, 93 NX2000, 00 Mazda 626 (Sold)
2016 NJMP Heroic Fix, 2017 NJMP Near Heroic Fix except we can't drive, 2017 Thompson I Got Screwed, 2019 Pitt Heroic Fix