Contemplating a Change to Class A from 5th Wheel

In looking at different models of motorhomes, I've found that the floor plans don't always correlate to the year the seller says it is. Sometimes you have to guess because the seller just says "2003 39' Kountry Star" so you have to look through floor plans to find one that matches to get the model number. Other times, you have a specific model, such as 2003 Kountry Star KSDP 3905, but it still doesn't line up with period literature. I don't know if its important, but its curious.