Not enough pictures and low resolution ones at that to tell. How is the house area in regards to wear? Notorious for wear around the inserts. I see some Factory Mylar edges in the picture. Is there Mylar over the House area? Look around drop edges and eject hole by thing.
Coin door looks to be touched up, missing bolt on top of coin door? Lots of scratches around the door. Agree it could be a diamond in the rough but would need a closer look. For 6K though I would expect it to at least be cleaned
If he refused 5K and it is in good shape try $5100. Doubt I would go 6K.

From the factory there was a piece in the pop bumper area and I believe one in front of the graveyard scoop. On the playfield image I can see Mylar edges. Since there is no Mansion pic it is probably worn but there was a Bally produced central Mylar that was available that covered the Mansion section. I have one on mine. Prevented the typical Mansion insert edge wear.

This might be the same or a close copy. http://www.marcospecialties.com/pinball-parts/03-7960-20017
The central piece was the optional one.