Introduction to Vintage Watches - Worth keeping an eye on?

Hello everyone!

In the past year, I've gotten into watches and my attention has specifically turned to vintage watches as of late. This particular watch caught my attention, what ostensibly is an Omega Seamaster ref. 2576-15. Having come from a background of collecting (Magic: the Gathering and firearms), I understand the importance of getting opinions from people who know more than yourself, and would appreciate guidance on whether this piece is legitimate. Unfortunately, the photos aren't great and I'm asking the store for better quality pictures.

Things that stood out to me:
- There is a lack of "Swiss Made" or "Swiss" at the 6 o'clock. Based on comparisons on this forum (https://omegaforums.net/threads/opinions-on-this-omega-ref-2576-4-pre-seamaster.112290) and c24 (https://www.chrono24.com/omega/seamaster--id25029685.htm), I don't know if this a huge red flag, something "normal", or even just an artifact of bad angles and photography.
- From what I could see online, there were a number of different indices used at the 12, 3, and 9 o'clock positions. I only found one similar example I could find seemed to match (https://www.chrono24.com/omega/gents-automatic-wristwatch--id15025119.htm, and that one had no Seamaster script on the dial.
- The markings on the inside of the caseback seem to differ, even within the same 2576 reference. Is it correct for this watch?

Looking forward to learning something and hearing all of your opinions on if this is something worth keeping an eye on, or just one of many frankenwatches and fakes that made it's way onto the internet. Thank you for your time, I hope all of you enjoy your long weekend!

Thanks everyone! I appreciate your insight. Having paid the noob tax before in other hobbies, I have no intention of repeating the experience here.

Aside from browsing these forums, is there a particular website or resource that catalogs the various Omega references? If watches are anything like Mosin-Nagants, chances are there are variations on variations of them, and I'd love to dive in and start building up my own knowledge.

Thanks for the resource, it's been very fun reading. Regarding the "take pix, ask questions" line, what's the etiquette around like? Would it be best to keep all my questions about individual watches in this thread, or start a new one for each watch? I'd hate to pollute the forum with unnecessary threads.

You’ve received great advice, as always. This reference is a great choice for a vintage watch, but you will kiss many frogs before you find your Prince. 😉 after a while the signs of an honest watch vs. a basket case will become more and more clear to you. The process is enjoyable.

Thanks for sharing that link! I know what I am going to be spending my time on this weekend!