My dealer took care of all the registration paper work for me. The reason they want you to register it, and why it's required, is for recall notices.
When we had our '03 Kiwi 17a, about 18 months after we bought it we got a letter from the manufacturer of the microwave. I called the number and verified the SN. They sent someone to my house (where the trailer is parked) to replace the recalled part.
So if your dealer does not register your RV and it's components with the manufacturers, make sure you do take care of it.
We've bought 3 Jaycos new, '93, '03, and '13. Not once have I received spam snail mail or email from any manufacturer.
2013 Jayco Jayfeather X20 E, 2008 GMC Sierra 1500 Crew Cab Z71 SLE