Yes I think they do. But you really ought to get a controller, so's you can switch off/on and regulate the heat as you're going along. You could roast otherwise! It will come with a male and female socket, so could be inserted afterwards. The Gerbings sockets are all the same type (also same as Warm n Safe, not sure about others).
So you'd wire in a female socket to the bike anyway normally, and may need to do this via a relay (if you want it switched), or could I guess do it direct from the battery. For instance a standard 1200GS accessory socket won't provide enough current, not sure about other bikes. The Gerbings in particular uses quite a lot.
Not sure I've explained very well, but if not please ask!