Mail van, how does it come apart?

[Hoss]

I bought 2 Bachman mail vans and I want to put an end of train device like tail lamp on one.
I've tried and I think I might be missing something, so any one else have better luck getting these apart? They have open interiors so my other one may receive some details like a post sorting room and mail sacks assuming they aren't too hard to come apart.

[Calebtrain]

It may take some working and plying with a screwdriver but the roof should kinda, pop off, shouldn't it?

[Hoss]

Welp, good news, I figured it out, bad news is that there are two screws holding the roof on from the bottom. It's fixable, thankfully, so now I know how to take the other one apart.

[RW James]

Good rule to follow: Always - ALWAYS - look for screws before you start prying things apart.