Battery and Rear Bulkhead question

8:1 BATTERIES
All batteries must be securely mounted; must be of sufficient capacity to start vehicle at any time. Batteries may not be relocated into the driver or passenger compartments. Rear firewall of .024- inch steel or .032-inch aluminum (including package tray) required when battery is relocated in trunk. In lieu of rear firewall, battery may be located in a sealed .024-inch steel, .032-inch aluminum, or NHRA-accepted poly box. If sealed box is used in lieu of rear firewall, box may not be used to secure battery and must be vented outside of body. Relocated battery(s) must be fastened to frame or frame structure with a minimum of two 3/8-inch-diameter bolts. OEM located batteries without complete OEM hold-down hardware must be secured to OEM battery box/tray using the same 3/8-inch- diameter bolt hold-down method described in previous sentence. (“J” hooks prohibited or must have open end welded shut.) Metal battery hold-down straps mandatory. Strapping tape prohibited. A maximum of two automobile batteries, or 150 pounds combined maximum weight (unless otherwise specified in Class Requirements), is permitted. Maximums may vary according to Class Requirements

I don't see anything in the rules that would exempt any relocated battery from either a box or a bulkhead.

Dennis