As far as I know ....
...magnets do NOT stick to plastic.
I'm not bashing anyones reproductions, but the GM emblem actually feels heavier and sturdier than the repro. (At least this one, circa 1989 does) I don't have a digital scale to weigh it, though.
Original GM emblem has an orange colored "peel off" with a tab. Repro has a blue "peel off" with no tab.
...magnets do NOT stick to plastic.

I'm not bashing anyones reproductions, but the GM emblem actually feels heavier and sturdier than the repro. (At least this one, circa 1989 does) I don't have a digital scale to weigh it, though.
Original GM emblem has an orange colored "peel off" with a tab. Repro has a blue "peel off" with no tab.