There is a catch 22 with that too. It's common knowledge that the chassis will probably be a year older than the RV house. Let's say your RV is 2018 and the chassis is 2017.
When you give your VIN to the insurance company, they only value the RV and it's contents as a 2017. So if you have paid for full replacement insurance, and it's totaled, they save a few thousand that way and you get the value of a 2017. I believe...and every insurance policy I've bought for my RVs over the years have shown the year older age rather than the house age. I checked with them 14 years ago about it but don't remember all they said...other then they weren't going to change it.