Hi,
If you can find the VIN number, we can back into the year; the model year is the 10th digit counting from the left. The first 3 digits, starting from the left, will be 1LC for Sunline. The 17-digit VIN may be stamped on the A-frame behind the ball coupler or on a tag. Have a look there and let us know the 10th digit, and we can decode it.
A VIN tag may also be present under the entry door threshold plate. Remove the plate screws and lift it up to check for a tag. Once you know the year, you can download a sales brochure for that year and use the floor plans to back out a model number. Our brochures are in the "Resources" section. When logged in, click the Resources tab at the top of the forum page. Scroll to Brochures, then scroll to the year to find the brochure.
If you cannot locate a VIN, then post pictures showing all 4 sides of the camper. Since it was not painted and has the original decals and siding color, we can back into a model year and floor plan. Your two pics are showing up.
Too bad that the window was broken and left open to the elements.
Hope this helps,
John