Opinions on this 1500, first foray into vintage??

[watchstuff]

Hi All,

Starting looking at vintage pieces and starting off small to begin with. Have seen this model, I believe it's 1500, automatic, blue dial, no quickset date. Supposed to date to the 1970's.

Just a couple queries:
1. The dial looks "vintage" to me, but am worried about the marks at 6pm/7pm, is that rust?
2. Also does anyone have this blue dial, it looks dark navy blue to me, was there a lighter blue available, but maybe it's just the photo?
3. Any other info on this model?

Any tips appreciated.
Cheers.