Thom, the heart taillights started in October '52.... for the so-called oval-dash splits (the dashboard changed to the oval-style at that time, also).
But yes, they are often seen on models that they don't belong on. I had a '53 Sunroof with NOS hearts and semaphores, back in the late '80s. *sigh*
Admiring your work from afar... cheers and salutations!
_