Baltimore cannot take their old name. The trademark on the name belonged to the team, not the city. When the team moved, they were allowed to take it. They could have changed it a la the Browns to Ravens when they moved in which case the teamname could be reused since it was no longer active. But no.
I dug the Ons joke. Pretty funny.
But seriously, I dig the Ravens. I like their name a lot. A good historical reference for the city.