Snakecharma is correct.
767 was originally designed as a 3 person flight deck - but late in the development program the FAA released a report that 2 crew was just as safe as 3 crew, assuming the crew work load was properly addressed. Boeing was already working on a 2 crew 'option' - after the FAA report was released the launch customers all elected to adopt the 2 crew option (basically implementing EICAS and deleting the engineer's station).
The first half dozen or so 767s were originally built with 3 crew flight deck - and the very first 767 (VA001) flew with the 3 crew flight deck. The others were retrofit to the 2 crew configuration prior to delivery - no 3 crew 767s were ever delivered, and VA001 was eventually retrofit to 2 crew. VA001 was never delivered but used a test bed for various projects including the initial PW4000, finally getting fitted with a super sensitive infrared sensor to track incoming missiles as part of the work on a missile defense system (aka 'Star Wars).