I recently purchased this 1978 Trillium
4500 and it has an extra skylight in it, behind the normal one, as you can see in the photos. I have searched all over the internet for one like it but I can't seem to find one. The skylight appears very much made in the factory since the trailer has the factory paint
still on it and it is on this additional part in the same paint
and the workmanship is of high quality. The guy I purchased it from said that the guy he got it from said that he purchased it from the guy "who made the trailers.." Ok, I am not sure I believe that but none the less, I have a 4500 that is different from the ones I have seen. I like it because the inside is taller than the rest of the trailer and it allows me (6'2") to stand upright at the stove. Was this a factory option? I am not sure. Can anyone help?