Seeking opinions on this '60s pie-pan Constellation

Hi all. I am considering buying the pictured Constellation locally, and would appreciate your opinion on its condition. (The photos are the best I can provide, unfortunately, as emailed to me by the seller.)

Apart from the non-original crown and bracelet, and missing observatory logo on the caseback (polished away?), does it otherwise look original/authentic? Also, I am bad at picking redials, too, so appreciate any input here.

The price is low enough that, if it is authentic, I'd be happy to pay a watchmaker to clean and service it, replace that crystal and get a nice leather strap for it, because the poor thing looks quite derelicte at the moment. Or maybe this is one to avoid?

Thanks in advance.

This I would avoid, even at a low price, it looks to me to be a redial, the text appears heavy and there are no serifs present. The marked minute track appears uneven from what I can see, there's also evidence of water ingress on the dial from 3 to 4. The case is over polished, the medallion is missing, the crown is wrong, the strap aftermarket and the crystal cracked, it's just too far gone in my opinion

IMHO this would be a bad investment unlikely to return the spend. It is not all about profit, but a dial like that is a poor starting point. It is not an uncommon watch, and the dial suggests liquid got inside the case at some point. It has had a hard life.
I heard medallions got removed off the back as they were gold and worth something just metal value.

Thank you both. That’s enough for me to avoid this. Appreciate your help.

I definitely would not consider a constellation without the medallion.

Thanks for the kind words and the link to Desmond’s blog. I will do some reading and keep looking.

Have a great day, all, and thanks again for your help.