I believe I have the exact same model with the original narrower guard. Inherited from my grandfather. Worked great until the old, damaged chord shorted out. I had to unsolder the wires from the switch terminals, and now these terminals are loose, and might touch. Looking for a replacement...
I believe I have the same model with the original guards. Photos posted here:
http://www.collectorsweekly.com/stories/123846-skilsaw-model-77-possibly-1st-generation
I am looking for a switch. The saw was running GREAT! Inherited it from my grandfather. But it came to me with the chord...