Shelby Williams Wood and Upholstered Chairs

I have two yellow and two orange chairs.  They are all the same style and model number.  All are walnut(?) wood with the brass/metal covers on the bottom of the legs.  Chair is 32" inches high and seats are about 18" wide and deep.  The tag on the bottom says:  Shelby Williams MFG CO, Inc. Los Angeles, California 117-75  Registration number CAL-9004

I contacted the company by website "contact us" and I received a standard answer of "we do not have access to furniture information from that many years ago."  

I would like to know if there is a value.  I am going to gently clean them because I want to keep the original upholstery since it is in good shape.