Seat Belt inertia reel bolts & bulkhead

[chrisbeck]

There's a chain of discussion on this from 10 years ago so I thought I'd better start a new topic.
I'm fitting new inertia reels in my Federal TC/Special. I have replaced the original fibreboard bulkhead with a Nidaplast honeycomb panel fibreglassed both sides. Can someone remind me what was originally in place where the seat belt reels are bolted through to the braces in the engine bay? Was it just a single skin of fibreglass or was the fibreboard sandwiched between the reel and the bracket on the brace?
Thanks,
Chris

[TurboFource]

Seems to me it goes through the fiberboard … out of town so I can’t go look …