TNFiddler...Hi and Welcome!
Wow like a blast from the past...I haven't heard of Open Road in a long time! My first Class A was an Open Road, can't remember the year now but it was around the age of your Class C. Mine was 22' and on a Fargo frame. Anyhow Open Road was manufactured by Open Road Industries in El Segundo, CA. Haven't heard of them in years, don't know if they were bought out, or went out of business.
You could contact the RV Hall of Fame Museum, they likely could give you more information about the company. RV/MH Hall of Fame - Museum - Library - Conference Center
Also here is a fun add for a 1975 Open Road class C Field & Stream - Google Books
Have fun fixing and camping in your new rig.