zOwie Omega Discussion Forum

Hello, I am an avid Omega owner considering purchasing a vintage seamaster to complement my newish gmt. I have been looking at several, and thought someone with considerably more knowledge than I could spare a minute or two and help me help myself.
I am looking at the 50's vintage calendar series. A few questions:
What are the most desirable movements for collectibility if any?
Is 18K solid rose, or pink gold worth more than 18K solid yellow?
What would be a reasonable price to pay for a first year issue, I think 1951 or 52 in what appears to be excellent with a 353 bumper movement(no scratches or dings, and crystal appears excellent) condition?
500, 1000, 2000, 3000 USD?
How do I know if it is a first year issue?
How important is an original bracelet to valuing?
What does 'signing' mean?
I tried the omega site to check the serial number, but couldn't figure out how to 'value an omega' on the website. Maybe I am missing something.
What do the numbers on the back of the case mean (not the ones on the movement itself but the back cover whatever it is called).
I am looking for a watch that obviously I love, and plan to keep for a long number of years, but to have it appreciate would be a huge bonus.
Any help or advice on this would be appreciated.
Of course, I don't want to pay a price that is obviously over inflated, but I wouldn't know at my knowledge level.
Thank you so much!