that would work if I had a key with the laser cut but it never came with one
dealer can cut the blank key, just take proof of ownership with you to the parts department, they look up the key code (gm backend) and enter it into the key cutter machine they have behind the counter, cut the blank and you are good to go.
just note as I already stated in order to "add" a key you need 2 working keys already otherwise you are at the mercy of a locksmith or dealer. locksmith is going to be cheaper than the dealer unless you are on good terms with them, mine charged me $35 but i'm special.....
fob's and key's are 2 different things and 2 different processes.
push to start "key's" I don't think have a chip. dealer can still cut the blank in any case.