beauty is in the eye of the beholder
Looks real pretty to me! - :up
"
nasty" is something you fix with a power washer. -
... or maybe a scrub brush, and some bleach/soap water.
Worse comes to worse, you spray paint it!
Let's see the back side, and tell us how many feet across it is.
I'd say 8 or 10 feet, but not knowing the diameter of the scalar ring, it's hard to measure from your picture.
(I've seen scalars in various sizes)
There've been pix posted here of similar dishes.
So, I'm sure someone knows the brand and has some comments on it.
If it's a commercial dish like a Channel Master (doubtful) with molded-in ribs on the back, that's a no-brainer!
However if it's some old fiberglass dish from the 80's, you might want to get a second opinion.
And as for the "seller", tell him if it's a good one, you won't charge to haul it away.
He's probably checked already and knows what a removal would cost!