Any red flags with this 50s seamaster?

Dial looks very wrong, case looks pretty beat up/poorly polished, and hands look like they have corrosion, plus a bad crystal. At this point, assuming it runs really well (which you'd need to confirm with a timegrapher), it would be worth a little more than a parts movement. $300 would be pushing it if the movement was perfect, though based on the rest, I'd doubt it.

Here's the the problem with shopping for low-cost vintage Omegas: They are all going to be in desperate need of a service, and that is going to cost you ~$500 (perhaps more depending on the condition!). And don't trust sellers when they say 'freshly serviced!', they all say that, and no one means it unless they have receipts from a WELL KNOWN watch maker (there are also a ton of hack watchmakers whose idea of a service is to open the case back, say 'looks good!', and close it back up).