chronoboy64
·Good god ... beware 

....here's the description of Good from the Timezone scale, which is still widely used for private watch sales:
Good
Nothing fundamentally wrong with the watch, though it has quite obviously been used. Running and wearable, but may gain or lose a few minutes over 24 hours. Case may show a few dings, nicks, or deep scratches. May have a redial that is not up to high standards. May not have all original parts. 77-82%
.......
I suspect the rusted 321 Speedmaster was purchased by someone who wanted a legit 321 Speedmaster serial #. it will be interesting to see how the watch gets 'transformed' when the auction buyer goes to resell for $9k.