Replacing or repairing ignition lock cylinder while keeping the original key bitting

[jodawill]

Has anyone here tried to either repair the original lock cylinder or replace it with one with the same bitting? I need to replace mine, but I don't want to lose the ability to use my grandpa's original keys.

 

As an aside, the copy he used as his daily key is so worn down it wouldn't work on a new lock cylinder, so I tracked down an identical key blank so I can recreate it. He never used the original keys, so I can still copy the bitting from them.

 

I'm not sure how to go about this. It looks like all of the cylinders on Rock Auto are configured for the included keys, and I'm not even sure whether those keys are even the same type (B46J). Is it possible to buy a wafer set to repair the original cylinder?

[eaglescout526]

I swear I saw somewhere that the GM ignition cylinders are not serviceable and a new one with keys was to be ordered. I could be wrong and they could flat out be serviceable and manufactures just used it as a way to move away from rebuilding lock cylinders. 

[jodawill]

This page says the lock comes both coded and uncoded, but I can't find any uncoded ones for sale.