Suggest you start calling your local RV dealers and ask their parts manager. Have a picture of the other lock to send them, from both in and out,. There's a chance they might be able to find something that works. I would replace the other one at the same time, or at least have a spare.
Report back on how you resolve this.
If all else fails, read the directions!!
What Dave said is pretty well spot on. Most auto parts stores can get you what you need to keep a car or pick up on the road. RV's we are pretty much stuck ordering parts from a dealer or if your lucky a site like E-trailer. There are also several RV recycle yards out there that you can google for used parts. The hood latches on a class A I woul think might be available through one of them.