I saved every key from GM vehicles we junked when I worked at a junkyard,and a body shop owner gave me a few hundred GM keys he had cluttering up his desk drawers one day long ago,ever since then,I haven't had to pull a lock or have a key made for most of the GM trucks I have bought over the years......
I just go thru them all one by one and try them,and so far I've failed only once to find one that worked in the ignition or doors,and I just had a copy made of that one...that cookie tin full of keys has saved some friends from having to have keys made or the locks and ignition swapped for new ones several times too....it appears GM didn't have that many different key codes from the 60's to late 80's...maybe 10 or so,I've been told...
I freaked my friend out when I started up his old Nova with my 81 G-10 van's ignition key one day,it was identical to his cars key!...I've been called to friends shops when they haul in a older GM and cant get the doors or trunk open or start them too,when they lacked keys...only a few times have I failed to find a key I could get to work...
You definately wont want to lose keys on a BMW,Saab,or VW,or Mercedes,some of the newer ones with chipped keys can cost up to 1000 bucks to replace,and you also will need proof you own the vehicle (title) to show a dealer,before you can get another key made,and then you'll have to get the computer "flashed" in order to let the new key let the engine run thanks to security systems....
