Messing with wiring might get that vintage vehicle to run... but how do you intend to unlock the steering wheel and remove it from park (assuming it's an auto trans), without the key?
My local dealer requires title, license plate registration card, or current insurance policy, with VIN and owner's name on it.... along with the owner being present and having picture ID. Depending on year and type of key, cost ranges from $10 (pre-electronics single sided like in a 1993) to $85 for a transponder equipped double-cut key. I have no idea how they handle the new "side-milled" type keys.
Just for general knowledge on key situations, some info I gained in 30 years as a pro locksmith... GM started cross referencing key codes with VIN numbers in their computer system in about 1990, so they should have the record of the 'original' key codes going back that far. But locks wear out and get replaced, and if the ignition lock was changed, their info is no longer valid.
The current cost of a replacement ignition lock cylinder for a 1993 GM truck (old, single-sided, 2 key system) is about $10 at a parts store. With the right tools & know how, it's about a 20-30 minute job. Remove steering wheel, remove steering wheel lock plate (special tool), unscrew and move aside turn signal switch to expose bolt head that holds lock in place. Some were 5/16" hex head, some were phillips head, later ones were torx T-20. Lock slides right out after bolt is removed, no key needed, new one slides right in. Reassemble in reverse order. Doesn't get much easier. It gets more complicated on a telescoping steering column, and those with airbags in the wheel pad... but I've ever seen an air bag nor telescoping column on any 1994 or older GM truck.
(most Chrysler products that had tilt wheels in the 1980s, early 1990s used GM style steering columns and lock cylinders, but with Chrysler keys. They could be interchanged... I had a 1989 Dakota LE with tilt that I installed a GM ignition lock into, when the lock failed and I had none in stock with Chrysler keys, but had a dozen GM key type locks lying around).
