To add, I have found on one occasion to be surface rust under the e-coat. May or may not have surfaced later - was glad I took it down to the bare steel.

1970 Charger - V10, 6spd, Alterkation, Street Lynx 4 Link, Moser Dana 60, Wilwood 14" disks, Forgeline 18" Wheels (Rear:335's), ISIS Multiplexing Wiring http://www.v10mopar.com 2012 Charger SRT8