Nice! 2K-3K is really not bad. I'm hunting Turtwig in Pearl, started last night so I'm only 150 SRs into my hunt. The SRs are really long in this game, so I'm hoping for an early shiny *fingers crossed* Do you remember how many days you were at the chimchar hunt?
If you really want aron you could always try repel tricking it for better odds. So on B2F of granite cave if you have a repel trick pokemon at level 12 the only pokemon you'll run into are aron and mawhile, with aron being the more frequently found pokemon.
My best advice for a legit copy is too look at any gamestores in your town? If you don't have any near you can try amazon and just check the seller's status and look at their reviews and see if there is a trend fo bad service or fakes. I know there are also videos online that show the differences between legit copies and common fakes so that might help when you get the game and remain unsure about its legitness.
Any luck with your shiny Treecko yet? I'm in day 4 of hunting and nothing yet. I'm debating on erasing the save file data and starting all over because idk all the YouTube ones I've seen so far were under 1000. It makes me worry a bit.