Well, Albatross, I have some good news for you. I was almost right.
The old E. Theo Ave., the part from Mission Road to the bridge over the river, is now named Theo Parkway. The new street that runs from Mission Road to the river, through the back end of what used to be Concepción Park is now Theo Avenue.
So the new street is now the old street, and the old street is now the new street. Which I believe is S.O.P. for San Antonio streets.