Those are some very large buldges, but the main "kicker" is the presence of pronounced/"deep looking" pre-anal pores (which I don't see in that picture).
When you are sexing geckos it is not a matter of age, but rather size. I can sex 95% of my geckos by 15-20grams, but every now and then you will have a male that does not "bloom" until he is larger.
If you want to be 100% sure then 30 grams is a good target size.
Hopefully "he" turns out to be a "she" for you.
Also, about the difficulty of selling males... it really depends on how many you have to sell. If you only need to sell a few you shouldn't have much of a problem, but if you are extremely male heavy and need to move 100 geckos (80 of which are male) it may be a different story.
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-Ross Payan - www.LeosAnonymous.com
Leos Anonymous
Ball Pythons, Red Striped Leos, and Screaming Fat-Tails