1) frame bolt is another name for flange head bolts
2) Currently as of 2010 49 CFR 393.201 states:
§ 393.201 Frames.
(a) The frame or chassis of each commercial motor vehicle shall not be cracked, loose, sagging or broken.
(b) Bolts or brackets securing the cab or the body of the vehicle to the frame must not be loose, broken, or missing.
(c) The frame rail flanges between the axles shall not be bent, cut or notched, except as specified by the manufacturer.
(d) Parts and accessories shall not be welded to the frame or chassis of a commercial motor vehicle except in accordance with the vehicle manufacturer’s recommendations. Any welded repair of the frame must also be in accordance with the vehicle manufacturer’s recommendations.
(e) No holes shall be drilled in the top or bottom rail flanges, except as specified by the manufacturer. 
Previously in 2001 49 CFR 393.201 stated:
 393.201 Frames.
(a) The frame of every bus, truck, and truck tractor shall not be cracked, loose, sagging or broken.
(b) Bolts or brackets securing the cab or the body of the vehicle to the frame must not be loose, broken, or missing.
(c) The frame rail flanges between the axles shall not be bent, cut or notched, except as specified by the manufacturer.
(d) All accessories mounted to the truck tractor frame must be bolted or riveted.
(e) No holes shall be drilled in the top or bottom rail flanges, except as specified by the manufacturer. (f) Field repairs are allowed.

Neither says frame bolts only.