67 C20 push start

[truckkeepsmesane]

I just bought this 67 C20. The guy I bought it from said he had it running last year but when I went to pick it up it wouldn't start. After rigging a better ground I turned the key and still got nothing. Then I noticed a button on the lower left side of the dash and pushed it on a whim. She turned over! Still not running but the engine isn't seized. I will trouble shoot that more later. My question is: was this a standard option or a previous owner modification?
Additionally the truck has a 67 VIN the traditional small back glass but also has the side markers like a 68. When I start my resto I think the side markers are going away. Thoughts?