Big Blue's younger brother is in town

I'm not sure where this bus came from, but it showed up down the street yesterday. I brought Blue down this morning for a photo op. The other bus is post-1972 - you can see the difference in taillights and turn signals on the front, as well as the roofline is a little different - Big Blue being more rounded at the top. Interesting that it has the exact same Riviera pop top as Blue.