I have a 20' 1985 funchaser and it doesn't look the same.
Measure from the ball hitch to the rear bumper and that is your true length. I wouldn't think it is a 16' since it has dual axles. No knowledge as to other models.
But what do I know!!!!!
From your outside pic the floor plan is very different than mine.
Mine has 2 windows on the side that you show, with the frig and power cord in between the window area.
Much cleaner and nicer looking than mine. Mine did have some peeling stripes when I purchased it. Now covered over with paint.
They are a great size for traveling. Mine has seen over 25k miles in the last 4 years.
Repairs are always needed when coming home from a long trip. NO big deal, it is 30 years after all.
Enjoy!
steve