I got lucky and found that it was showing on a movie channel one time when we had some free movie channels for a while due to some promotional thing DishNetwork was running. This was a few years ago. I had always been interested in seeing this movie, because 1) it was a comedy about the Alamo, and 2) someone I know was an extra in it.
If you haven't seen it, I recommend it highly because it's still very funny. It stars Peter Ustinov as Mexican Army Brigadier General Maximillian Rodrigues DeSantos, John Astin as his somewhat sadistic seargent, and Harry Morgan as the cranky chief of police. Other names you'll recognize are in it, like Jonathan Winters, who plays the owner of a mattress store who is also technically a brigadier general in the National Guard, and character actor and perennial wacky next-door neighbor Alice Ghostly (who thinks the Mexican soldiers are Chinese communists invading the United States). Oh yeah, Keenan Wynn is also in it. If you watch it, you'll most likely see other faces you recognize but whose names you don't remember, like this guy, or this guy, or this guy.
Unfortunately, these grabs are not of the highest quality, but I hope that if you still remember San Antonio in 1969, you'll recognize some of these scenes. I tried to mostly stick with shots that show buildings and signs in the background that could trigger some memories. Please feel free to leave comments about any of these photos. Click on the pictures to see larger versions (but not a whole lot larger).
And here's a clip with Jonathan Winters, just for fun.