This upgrade was done for us by Grand Design and Lippert for us to test them out. From what we understand, to get the doors, you need to go through an RV dealer since it's not a simple DIY installation. There are some measurements that need to be taken to see if they will fit. Some RV's with the older model have the happijack system too far back to allow installation. For us, we barely made it and only because we had removed the benches from our happijack.
We'd recommend contacting Lippert directly to ask since availability and polices are always changing.