If it seems it is unlikely, it probably is.
I found multiple images of buses without black stripes. In fact I found one where the “floor” black line merged with the center one and then dropped back down. I strongly DOUBT the floor of the bus had an 8 foot hump.
https://designtaxi.com/news/415388/Here-s-What-The-Black-Stripes-On-School-Buses-Are-Really-For/
Follow
@feloneouscat if you noticed - the pictures you included were of newer modeled/designed buses compared to the original I tooted... but I deleted it