I have one that looks just like it but is labeled as a model 1563 instead of a 585 - I don't know that I was ever able to definitively date mine beyond "probably mid 50's". I'm also not sure what the difference between the two machines is - I'm looking at the photo of mine right now and I can't spot any differences!
[ATTACH=CONFIG]576349[/ATTACH]
I can tell you that mine sews very nicely, though. Get yours cleaned up and you should have a nice machine!