Vintage seamaster cosmic

Hello everyone. I found this vintage seamaster cosmic for sale, I think it looks good but I’m not quite sure about a couple of things. First of all, the seller says he can’t open the case, therefore can’t provide pictures of the movement, so since I’m no expert I can’t tell if it’s original or not. Secondly I would like to know if you think the watch has been polished. How much should I pay assuming it’s legit and taking into account that I can’t see the movement . Thank you very much in advance!!!!

Thank you very much!!!! Do you think it’s legit though??