questions about my Rolex's

[motulken]

Hi I am new to this forum. I have a Rolex that my father gave me when I graduated college in 1981. I am thinking about selling it. I have someone interested in buying it and another Rolex i have for $12K

Here is my question. The watch is clearly marked 1665 and does have the gas release valve. The back has patent pending on it. The serial number is 352xxxx.
So it should be a sea dweller papers say from 1974. I have the box, paper work, certificate etc. The issue is that the dial does not say sea dweller is says Submariner. The buyer suggest that at some point the dial was changed.
What do you experts think.

I have an Explorer too, It is from the late 60's probably 1969. I have no box or paperwork for it.
He is interested in buying both for 12K. Good deal or not? I thought they would be worth more.
Thanks in advance for any help and opinions.