Car show sticker question

[BoostedPontiac]

I bought my GTP a while ago and im wondering what the stickers on the back window mean. One is "MGM 07" then the one above that says "MGM 08". Any ideas what that stands for?

 

[Explicit_Spade]

Are there images or just the letters? Where did you buy the car from?

 

[BoostedPontiac]

Its just the letters and i bought the car from the grand rapids area in Michigan

 

[BoostedPontiac]

Here is the sticker

 

[theaceofspades]

Probably an event that he went to two years in a row