Why can't I use my Arceus in random Battle Rev Wi-Fi battles?

It annoys me quite a lot battling other people in random Wi-Fi battles and seeing them using Arceus identical to mine. The only difference is the plates they hold. Every time I have Arceus in my team, it says there is a pokemon in the team I can't use on Wi-Fi, Arceus obviously.
I got my Arceus through Mystery Gift from Target's event. I've seen others on Wi-Fi from that too. It's annoyed me for too long, I only made an account on here just to get this question answered -__-

Stats:
OT: Michina
ID Number: 11059

Quiet Nature
Nov 15, 2009
Pokemon Event
Apparently had a fateful encounter at lv. 100
Mischievous
Likes Dry food

HP: 369
Atk: 275
Def: 270
Sp. Atk: 303
Sp. Def: 249
Spd: 229

Moves:
Judgement
Roar of Time
Spacial Rend
Shadow Force

Thanks!

Erhm...

Really dunno..

Are the Arceus they use identical in moves, too?

Because maybe Battle Revolution count these as illegitimate moves for Arceus.. (games from 2007 FTW!)

Yep, I battled an Ice Arceus today who kept spamming Shadow Force -__-

Good for him.
Next time use Judgment.
But this arceus looks like a hacked one to me.. Or rather a strange event.

My best guess would be that because that event was held so much later, it's counted as illegitimate on PBR. If you have any other questions you need to get answered, please use the Q&A threads for it. Thanks~

Locked.