Often came with a page detailing the "strange similarities" between them... check out https://store.ushistory.org/products/abraham-lincoln-john-f-kennedy-coincidences
A nice counter stamped cent. It’s called Kennedy looking at Lincoln. You can buy these new for about a dollar. Neat to find on your own.
Your cent with the JFK stamped on it is one of at least four different type of JFK stamps. The hair line looks like this one with two short lines. I have this one labeled #3. #2 has longer line in part of hair. no "S" in ear. #1 has multi -line at hair part and V at end of sideburn. No jaw line and a better smile. #4 is labeled for those who do not recognize the profile of JFK.
They have been around since at least 1964. As far as I know they are not from any kind of series. Folks just been remaking dies, stamping cents and selling them as a novelty and making a profit. A couple of mine have a glue spot on the reverse.
I think it was an ad in Boy's Life that prompted me to buy one of those "Kennedy Looks at Lincoln" cents. Also got the "Lincoln Smoking Pipe" variety.