Thanks for the warm welcome, all! Here's another pic with the top up. The car's in great shape mechanically, and I've spent some time over the last year putting in A/C (vintage air), disc brakes, etc. Next step is some interior rehab.
I was told that Plymouth made a variant of the Valiant for the Mexico market called the Acapulco, and the Barracuda grill was one of the minor things that set it apart. While I have no way of verifying this, the story goes that some California dealer bought a dozen of them in '65, and this is one from that batch. Maybe a little far-fetched, but sounds cool nonetheless!
Nice 65! That grill does look like the "Acapulco". They also had a built in tachometer or maybe a clock in the shift console if I recall from pics I've seen.