When to lock Hubs

[the evil twin]

I have auto locking hubs that have a hex bolt head in the center where I would expect the manual twist to engage to be. Is it possible to lock these in manually?

Yes, the nut is the same size as the wheel brace. They have two settings "Auto" and "Lock"

If you are going out into gnarly/muddy terrain for a wheel you should use a wrench and "lock" the hubs. "Auto" is essentially only for a 1 off spur of the moment use when you don't want to leave the comfort of the cabin unlike GQ's where people want every excuse to get out.