That's sweet in a scary way!
All I ever do before firing up an old electric tool is to check for shorts to ground/case. Looks like someone already updated yours to 3-prong. From the looks of the gearbox, it might not be possible to move the chain by hand, but I'd give it a try.
I'd also put a much longer cord on that. At least 25 feet. I use 12 AWG extension cords for re-cording old tools.