I think the MSRP was somewhere around 17-20k, but that's a very rough estimate. There is a book at the RV/MH Hall of Fame library in Elkhart, Indiana that lists all the original MSRP's (base price, no options). I don't remember the name of the book, so I can't tell you where to find it. The best deal is to talk to your nearest Sunline dealer and see if they remember 2003 pricing.
2007 T-286SR Cherry/Granola, #6236, original owner, current mileage: 9473.8 (as of 6/18/21)
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