Don't mean to be a thread necro but this thread turned up for me when I had a similar problem. I too appeared to never to have received my Gifts of Exploration but had 100% world completion. Searched all my inventories with GW2Efficiency.com api key search. Double checked my completion. I sent Customer Service a ticket with a couple of screenshots of map completion and the title achievement "Been There, Done That." They were very helpful and reimbursed me within like 4 hours.
For future people searching for help and getting this thread though, I noticed something that would have been very helpful when I got the Gifts of Exploration in the CS mail. They set off a bunch of collection achievements when I claimed them from the mail. All of the achievements were related to the Gen 1 weapons. Knowing this up front would have been very helpful but the achievements weren't listed on the Gift of Exploration wiki page. So search for achievements like "Legendary Weapon: Twilight" or "Legendary Weapon: Kudzu" if it's your first character with map completion. If the Gift of Exploration is grayed out and you have 100% world completion, then you are bugged like I was. Submit a ticket.