The usual spot for the manufacturers' branding is forward of the location shown and on the magazine well but on the left side of course. Panhandle may have tooled out the lower but I don't think so. My guess would be a manufacturer of lowers that doesn't mind building lowers without their branding and will instead put any or no name on the lower. The situation that I refer to is not unusual. You could ask Panhandle Powder Coat who built the lower. They most likely would remember. Maybe they still do it.
It appears to be the same address for Thermodyne and Panhandle Powder Coating. Maybe different companies under the same corporate umbrella?
I poked around on their website an found this - "PEC Armory is a full service NFA firearms manufacturer with a focus on military and law enforcement products located in Pensacola, FL. Our ultra precision products featured are fully automatic rifles and components. Based on the M4/AR15 platform in multiple calibers, including suppressors and barrels."
According to the site, they have precision milling capabilities at one of their subsidiary locations in Brewton.