(the 4k was a typo FYI, I'd meant to say 3)
If you'd rather have the Explorer than your Pilot, why not?
It really all comes down to what's motivating you to have one watch vs another. At the end of the day, a Swiss timepiece is an emotional purchase and many $10,000 watches are effectively not that much better than many $5,000 watches. If you're thinking in terms of comparing which would sell for a few hundred bucks more, I'd push back and say what difference does it make? You want what you want and you should have it if you can.
Personally, I would want at least the original bracelet for the Explorer. No documents plus no original bracelet is usually a red flag for me (especially if it's coming from Brazil or somewhere with high Rolex theft). And OEM Rolex bracelets aren't exactly cheap.
Also, if the proposed trade is occurring online in lieu of a direct Paypal transaction, double red flag. If the guy just kept your Pilot there'd be no recourse.
I don't mean to scare you off from what could be a very gratifying trade. Just trying to play devil's advocate.