It's fairly common for motorhomes to be built on chasses bought earlier by the manufacturer. My '89 SOB was on a Chevy '88 cutaway van chassis. My '94 Breakaway is actually on a '92 chassis/drivetrain (but it's the prototype for the new 28' Breakaway, so the lead time is normal); chassis was built 2/92, coach was complete 4/93 as a'94 model, which is how it's titled.