Wikipedia
Thar ARMALITE AR-15 was a variation of the Stoner ARMALITE AR-10. Both were SELECT FIRE, meaning they were capable of full auto fire. When Colt bought the Patent in 1959 they changed the name of to the M-16 when they sold it to the Military. until that point they were all full automatic capable.
When Colt introduced the civilian version of the COLT AR-!5 for the public it was not select fire and was SEMI AUTOMATIC ONLY.
The COLT AR-15 is the one everyone talks about that is available to the public, not the Stoner/Armalite select fire one.