Advice on Tudor 79090 Purchase

[dpt.calvin]

Hello, all. Long time reader, first time poster here. I am in contact with a private seller about purchasing his Tudor 79090. I have never purchased a used watch before, at least not of this value. He is asking $5900 but I offered $5500 and he seemed agreeable.

Prior to completing this transaction, I figured it would be in my best interest to do my due diligence. I understand there are thousands of replica Rolexes floating out there. So I looked to see if there are replica Tudors, as well. And of course, there are.

Would a Rolex dealer be able to verify the authenticity of this for me? If so, do they typically charge anything for this service? I've tried ringing my local AD but the phones keep ringing (must be working with a skeleton crew during these times and unable to answer the phones).

And based on these pictures, do you see any red flags? I understand with vintage watches that original parts are key. I have done some research, but my eyes are still untrained. Can you spot any parts that may have been replaced during service that are unoriginal?

Thanks in advance!