Like Steve I have only seen them where the wire is pushed into the moulded plug and engages with the internal spring., the ones S/S used to do are quite neat and use this method. The other alternative is the flat clip type where you solder the wire to the clip, I've used these but they look better on period engines and you have to watch out for arcing as there is no insulation.
I would think anything that needs welding or has a clamping screw may look a bit bulky but depends on the look you are after.