Stant makes a locking version 10572 and a non-locker primarily for the 71 and later 10800. I've removed the warning label from a 10800 and re-finished two to match the Dart and the Demon respectively. It's my fall back in case I loose a cap.
I had called Kragen and they said they did not have a cap that would fit my car. I called them just now and gave them the 10800 number and Oh yeah, we have that in stock $7.99"
They wont let me park here at work, I am next door at a grocery store hoping they don't tow it.
I ordered one of those nice looking caps from Damraider yesterday, after he confirmed it fit fine on his wagon, but I might go buy that stant one too, just to have a back up, and so I can park here in the morning.