late 60's to early70's Buick used car lot sign

[69_Mean_Mopar]

This has been in my family since we bought the used car lot from Drysdale Buick on Grand River, Redford, Mich. Spring of 1968. it is in Really Great shape. Two sided Red white and blue. Says Resale on the top red part. A blue check mark in the white center and cars on the bottom in blue. it is a big aluminum frame. I have never seen one. I cannot find anything close. A sign guy offered me $4800. Is that a good Price or too Cheap. Any input I would appreciate on this.