Info/advice appreciated on 1959-61 Constellation

Hi all,

I'm a timepiece noob but recently found a Constellation at an estate auction that I couldn't pass up.
It was purchased without papers or service history knowledge so it was a gamble for sure.
It turned out to be in pretty decent condition upon receiving it.
I had it looked at and serviced by an independent Omega repairer in Melbourne last month, and it only required a clean, oil, and new strap.
I've also taken it to the Omega store in Melbourne cbd earlier this week for some additional information and requested some pictures of the case back and movement (still waiting on these to be emailed through).
They did provide the following information after the tech opened it:
Cal: 551
Cal No. 1773****
Year: 1959-61
From my research, that cal no. would make this made in 1959.

I just have a couple of questions regarding this that I'd appreciate some input from the experts.
- Does it appear to be original? Does anything stand out as being replaced?
- Can I look at this purchase as an investment? Is it likely to increase in value over time based on the year, cal, 2 lines instead of 3 (no "officially certified" line? I know this is certainly speculative at best.
- If I were to sell it (which I'm definitely considering) what could I expect to get for it? I'd like to avoid eBay.

Photos below:

Thanks for your time! (hah)

You bought it and wanna sell it for profit, right?

Your questions regarding the originality should have been answered by the watchmaker that serviced it as he/she inspected it closely.

You are asking a lot of the watchmaker. It might be possible to indicate replaced movement parts that are not original but, no-one can know every dial/hand/case variation and that's not really the watchmaker's job as it's more of a historical issue.

As @cristos71 says, it looks a nice watch and correct but, I happen to know these and I have one. If someone sends me a Zenith bumper, I can't be sure that the dial and hands are original to that watch so, can only judge based on looking under a microscope for flaws - it's not easy to state anything about originality with certainty. Just bear in mind that you shouldn't expect a watchmaker to make the call on originality of everything.

Cheers, Chris

It's a particularly nice example and looks totally original. That's onyx inlay in the hands and markers. The rubs on the crystal will polish out and it will look even nicer then. This is a high-quality watch which as a beginner you could learn to truly appreciate if you took the time. If you are not desperate for money, why don't you keep it as a dress watch?

Thank you all for the responses!
Unfortunately, the initial repairer didn't give me much info, other than it was a nice watch and was keeping time well (this is before I even knew the anatomy of a watch, or the correct questions to ask).
I also only dealt with a sales rep at the Omega store and came back later that day to collect it after the tech had looked at it and scribbled some basic info on the back of a business card.
After reading your replies I'm inclined to keep it.
I'll do a bit of digging on the history of these too.
Thanks again!

Thank you. It's settled then, looks like I'll need a silver cloth and a box to store it in now.... although I'm kinda paranoid so I'll probably end up wearing it mostly!
I appreciate the responses and insight!

Exactly!! It's a beauty so wear it and love it. The original buckle is a real plus, and the strap is IMHO perfect for it.