The 1016 ran for roughly twenty-six years, the longest production of any Explorer, and long enough that the reference is really a sequence of eras wearing one number. Gilt gloss dials give way to matte, chapter rings come and go, the caliber moves from the 1560 to the 1570 and gains a hacking seconds mechanism in the 1970s, and the Superlative Chronometer Officially Certified text settles into place. Production ended in 1989 by every account. When it began is a genuine three-way dispute: 1959 in accounts tying it to the caliber cohort that produced the 5512 and the 1675, 1960 in some guides, and 1963 in most modern references. The file records 1963 with the dissent attached rather than adjudicating it.
That length is also the reason it is the Explorer most people have handled, and the reason dating one properly matters. The dial generation, the hands, the movement and the serial all have to agree on an era. A 1016 is easy to buy and harder to buy correctly.
The reference where dial variants do the pricing and the serial alone tells you very little. Buy the era, not the reference number.
Production windows and specifications compiled from documented collector references and period catalogs, cross-checked across independent sources; manufacturer records for this era are approximate by Seiko's own account.