A "what-if" scenario - 1680 instead of 5513

[fizz]

So after a few unsuccessful attempts and near misses at acquiring a 5513 Maxi from my birth year (79) for one reason or another (shady sellers, service parts like bezel, case pitting etc.) and following email exchanges with very renown sellers who have these models at present in near pristine condition, but at upwards of USD 10k, way, way outside my budget of 9k, I came across this very, very lovely looking 1680 for a price I can afford.

Isn't that the saying around these parts...buy the best at the price you can afford?

This seems less of a compromise than many of the other 5513's I've seen, and comes with box and papers. The dial looks lovely, lugs are strong, CG looks decent, pitting - no expert but looks minimal.

While the seller says its from 79, the serial no actually places it as 78 (but these are just...approximations).

No problem, the papers clearly show sold in 80, so its from the era (very late 70's, or very early 80's) that I've been interested in.

I'm not sure I'd take it because I'm not a big fan of the cyclops, but if I were to get over that (I tried a sapphire 16800 at a vintage store here locally and really liked the overall look of it including the 4 lines of text, balance of dial be damned!) I have a few quick questions:

1 - Is there anything alarmingly wrong with the watch?
2 - What is this dial called? Maxi 1, 2 etc? Same considerations as 5513? I get my second hand knowledge of 5513 dials from the excellent Beaumont Miller site. Using that, for 5513, I can verify which dial is what. What about 1680. What is this dial called? Is it considered good, bad or middle of the road?
3 - The plexi looks different. I assume this is not the domed T19 found on 5513 but still plastic? Is this the one called top hat or something? Of course, I prefer the look of the 5513 over this but this is just such a good set overall (I think).

Thoughts welcome, as I continue to evolve in my knowledge and choices.