The Classic designation was created to indicate the style of trailer that you have, a classic stick and tin style with regular cloth interiors and typical RV fixtures. This was compared to the Ultra style created by the interior designer in 2006, which included fiberglass exteriors, leather interiors, LED lighting, flat screen TVs, etc.
The Ultra package was available on any Sunline through 2007 as well, but they were rare. The Classic designation continued onto early 2007 Sunlines- the ones that were built while they were still building '06 models. Mine has the Classic decal on it, but the spare tire covers most of it.
In addition to the Classic decal, all the '06 model number tags by the entry door had "Classic" after the number.
You could try Dave King to see if they have any.
2007 T-286SR Cherry/Granola, #6236, original owner, current mileage: 9467.8 (as of 5/26/19)
1997 T-2653 Blue Denim, #5471
1979 12 1/2' MC, Beige & Avocado, #4639
Past Sunlines: '97 T-2653 #5089, '94 T-2251, '86 T-1550, '94 T-2363, '98 T-270SR