Firewall Insulation fasteners

[MyRed67]

  I am wondering how many fasteners were used to attach the Firewall Insulation on a early '67 Coupe W/O Air.  I'm getting some conflicting information.  Some of the Dealers say you need 4, I'm looking at the 67 AIM - UPC 1  pg. A6.5  it shows only 3.  I saved 2 taking the car apart, the one in the middle and the 1 lower right in the diagram.  And I believe I found the hole for the one at top
above the accelerator.  Any body out there know, is the AIM correct?  Or is there another one somewhere?