How do I know if my White 2 isn't ROM hack?

Question

So I am playing this White 2 game, everything is somehow so much different from other people's games. Such as my game's league four is already in Lv. 70 and above. The leaders and trainers have unbelievable smart moves. Furthermore, I have been catching all kind of Mythical and Legendary from different regions. I don't understand if I got a ROM hack game or it's just a special version? Bit confused

Comments

What legendaries and mythicals have you been catching and where did you catch them? Have you beat the Elite 4 once prior to them having the high levels? Do you remember what specific levels and moves they used?

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I caught the lengendaries and mythicals in all kinds of places, the other day I found a mew on lostlorn forest, I found a shaymin om route 14, a deoxys in giant chasm. I could go to Liberty Garden without a Liberty Pass and catch Vicini...
I have not beat the league four yet, I can't, it is so hard

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Yeah that's definitely a rom hack.

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Post a picture of the cartiridge?

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Thats hacked, though i kinda want to play a game like that

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This is certainly hacked, you can't catch mythicals and legendaries from different regions on random routes in White 2. White 2 E4 doesnt have level 70+ mons outside of rematches either.

Answer 1

This copy of White 2 is certainly hacked for the following reasons:
1. It is not possible to catch legendaries and mythical Pokemon(specificaly Mew, Shaymin, Deoxys) through random encounters on various routes in an unmodified copy of White 2.
2. The White Elite Four do not have level 70+ Pokemon the first time you challenge then, they only have level 70+ Pokemon in rematches.
General tips to detect hacked/bootleg cartridges
1. Find an image of a legitimate cartridge of White 2 and compare it side by side with your cartridge. Search for differences or errors in artwork, spellings, logos or trademarks. If there are any differences or errors, your cartridge is likely to be hacked or a bootleg.
2. Legitimate cartridges have the serial number NTR-031 stamped on the back side.
3. Check the levels of the gym leader's mons on your cartridge against their levels listed on this website. If there is a mismatch, your cartridge is hacked/modded.
Detailed instructions for identifying bootlegs are linked below.
Source:
https://pokemondb.net/black-white-2/gymleaders-elitefour
https://gamefaqs.gamespot.com/boards/989552-pokemon-black-version/79361268?validate=1
TLDR: Your cartridge is certainly a ROM hack.