Remove the spark plug washers or not?

Hi all,
was about to buy new plugs for my 1963 Dart w 225 engine. I was assured that I must remove the washer seals from the plugs if my car is 1963 to 70-something. Well, I just read that with early heads (60-62?) you must NOT remove them. My Dart being a 1963, there is a chance that the head is actually a '62, right? How can I tell the difference?