Howdy
@herod! Welcome to the 600 club. Its a great bunch of folks.
I am afraid I can't say for certain if your car is a Fiat or a Seat. I can say that the front badging and trim looks different than what I have seen on Fiats and a quick bing search uncovered this Seat:
The front trim and emblem on your car looks a lot like the one in the picture. Your car must be earlier than this one since yours has suicide doors. Thats a good clue. Your car also looks to have smaller headlamps.
The interwebs say that 797,319 Seat 600s were made, starting in 1957 - 1973, and they started exporting them to south america (and other places) starting in 1965. The cars are stamped sequentially, so your car is the 549,700th one made of whatever it is. With an assumed annual production at about 50k per year... that puts your car more like a 1968, as my best guess. This also lines up with the switch to traditional doors in 1969 and bigger headlamps.
I found all this info on wikipedia:
https://en.wikipedia.org/wiki/SEAT_600
For what it is worth, my car is a 1960 Fiat with a VIN 100-665274. If your car is actually a Fiat, then it would be more like a 1959. Makes so much sense, doesnt it?!
This thread is great for helping sort it out the Fiats... maybe it will help you too:
https://www.fiatforum.com/threads/600-vin-identification.275830/
Good luck and have fun!