Identify this ignition switch

[Marcosmadness]

This is a photo of the hole in the dash of my 1959 Chevrolet Step Van for the ignition switch. Note that the hole , which is approximately 1" in diameter, has two slots to keep the ignition switch cylinder from rotating after the nut is tightened. All of the replacement Chevrolet truck OEM style ignition switches I have seen have three slots and they are spaced differently. In addition, the ignition cylinder has a nut with 4 slots for tightening (the original nut was used as a spacer to hold a universal type ignition switch). All of the OEM type nuts I have seen have 3 slots. The wiring to the back of the switch appears to be original and uses ring tongues instead of the more modern slip ons/fast ons. Does anyone recognize what switch should go here (Year, model, and where a new replacement switch could be bought). I have a new 1959 Chevrolet truck ignition switch I could use but I would like to use the correct switch if I can find one. Any ideas?