I bought this 1964 Omega Seamaster and I'm hoping to verify is authenticity

Hello, everyone. This is my first post. I picked this 1964 Omega Seamaster 600 from Goodwill online auction for $200. I was hoping to gain some insight about it and it's authenticity. From the research i've done the movement serial number puts it in the correct time period but I'm certain the crown isn't original. I have no idea when it was last serviced but it seems to keep accurate time. However, I just got it in the mail today so I am unsure as to how much time it gains/ loses yet. Any insight into my $200 risk would be much appreciated. Do I have an overpriced fake, a parts watch, or something I should invest in servicing and cherishing?

Thank you all in advance for your time!

Get it serviced before you wear it.

Hi,
Welcome to the forum, I am relatively new on the forum myself. Your watch appears to be correct, the model to the case and movement, I can't tell from the pictures if the dial is original or refinished, the minute hands looks different then the hour hand unless it's just the glare in the photo. The watch appears to be from 1964-65, I'm sure one of the fine members here will be able to verify the watch for sure.

The minute hand has a tiny slit down the middle and the hour hand has the same slit but a bit of black in the middle. The 6 sided crown doesn't have the omega symbol on it, so I'm assuming not original. Do you know where I could look for a NOS crown? I plan to get it serviced as soon as possible.

I certainly plan to!

The crown would be after market if it isn't signed, it is not the correct style. You would need a 42056 crown reference, that would be the old reference, I'm not sure if omega still supplies that number or if they have change the reference number.
They should be able to replace the crown and gaskets with proper genuine parts when you have it serviced.

did some googling and it looks like that's still a valid reference! Thank you so much