Can you get a build sheet for a chevelle like you can with a Pontiac thru PHS. I found what appears to be a computer punch card in my 1968 malibu what is this?

Only if the car was built or sold in Canada. GM Of Canada will send you an information sheet since they have all their records. Other than that, nope. Also, no one has ever found a build sheet in a 68 Chevelle.

Paperwork you're more likely to find, if you're lucky, is either a Body Broadcast Copy or a Chassis Broadcast Copy. The Body Broadcast Copy will have such information as VIN, trim items like mirror options, radio options, steering wheel/column options, body emblem piercing, etc. where the Chassis Broadcast Copy will include drivetrain, suspension, and such.