Depending on your price level, there are only three out-of-the-box vintage Explorers to consider:
At $100, there's Narikaa's 21J Explorer: Standard classic Datejust rep with a great dial for the price. Drill lugholes for a superb 1016 on a budget.
At $248, Trusty's 1016 comes with a very good dial, a much nicer movement, and drilled lugholes. Shame they're too small and in the wrong place, but no one will notice--except you.
At ~$360, find someone (like Narikaa) to buy you an MBK 1016, which is hands-down the best vintage Explorer out of the box. Excellent dial, a much better and more authentic-looking case, and correctly-placed (but still too small) lugholes. However, like the other two, its dimensions are not identical to an actual 1016, so forget about changing the crystal.
Beyond that, it's franken country.
EDIT: Whoops, bad link.