Congrats on the new boat.
I believe what you may have is a 1980 South Coast Explorer 21.
There is an owner's association ( South Coast Owner's Association
) that might be helpful to you.
Also, some photos of an E21 here:
South Coast Sailor Talk...... The #1 South Coast Site on the Web! - 1981 Explorer 21
P.S. The title is missing one of the digits that appears in the HIN. You might want to get that corrected when you register/title the boat in your name.