First, the Bigsby could well be factory installed. Back then, they were much more amenable to doing customizations like that I can't tell for sure if it has gold or silver hardware. Normally the 555s come with gold hardware, but lots of people opted for chrome or nickel, and the factory would gladly accommodate. Also, having Lollar pickups would not be unusual. The Imperials are very good pickups. When you check it out, see if there is something on the label inside the F-hole.
As for the "crack", that might well be a reflection from the trem's arm, not a scratch. A crack would be unlikely as it doesn't seem to follow any grain, and the semi hollows are laminates with the grains between layers going crosswise which can resist the development of cracks like that. I zoomed in on the full size frontal shot, and didn't see the same type of line.
I have a H-535 it's an absolutely GREAT playing guitar. The only question is if it feels comfortable, and sounds good to YOU!