Steve,
The Monaco purchase of Beaver was in early 2002, so the 2003 models were Monaco designed. Obvious design changes that Monaco made in the 2003 models were the addition of slideout toppers, Cummins engines in some models (as opposed to the Cat engines that were used exclusively by SMC), and the Monaco preferred Aladdin engine monitor (SMC used only Silverleaf because the son of SMC's owner owns Silverleaf).
The 2003 Beaver Monterey, Patriot, and Marquis were all built in the original Beaver factory in Bend Oregon that the founders of Beaver still own and Monaco assumed the lease on as part of the SMC purchase.
Gerald