Strange window crank retainers

Anybody had to deal with these? Parting out two 65' Cuda's and all was going well until I encountered these damn retainers on three window cranks. All the others were the standard allen head, I've got a pretty well stocked toolbox but damned if I've got a socket with a small enough OD to fit inside this hole. Pic makes it look bigger but trust me it's pretty damn small. Going to drill it out if I can't find a solution and not wanting to grind the od of my sockets down. Gotta get past this SOB retainer, I need the regulators and glass,lol.