I recently lost my RV door keys and was in process of hving them replaced by GS service call to locksmith. My neighbor with a different model of Coach tried to open my door and low and behold it open...
Search RV key replacement and you will find about 6 key numbers being supplied for almost all locks. Some RV supply facilities keep a stock of these on hand for easy purchase. This just tells you how easy it is to get into your RV. My service facility recommended I search out a good quality lock replacement or invest in programmable lock replacement. I was just as surprised as you.