I've posted these photo elsewhere in the past, might as well post them here too.
Here's what the SAL B7 Turtleback roof looks like:
The ends don't have the small "darts" you see on the PRR cars:
Seaboard had single and double-door cars:
Here's what the PRR cars looked like, notice the small "darts" and the way the roof indents from the sides at the top:
Look at this beauty, love that style of lettering. Looks like it's made of Hershey's chocolate: