Off-Metal Nickel Error?

Picked this up at a local flea market this morning for a pretty low price. The gentleman had it in a case with some common date wheat pennies in a 2x2 labeled "Off Metal Nickel Error" next to a bunch of used VHS tapes. Seems like it's the real deal but just wanted to get a few opinions to see if I wasted $20 or not. Does this appear to be authentic?
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Comments
Is it the same size as a normal nickel?
I'm not an expert in this area, but the coin looks acid treated to me. What is the weight of the piece?
Is the planchet unusually thin? If so, I would be suspicious.
thecointrader
It's genuine from the picture (size and color appear right).
$20.00 may be the proper price for the error and condition.
1980: 95% copper, 5% zinc, 3.11 grams.
Jonathan
It's worth about $100-$150 in that condition.
Ledzep, I'll try to take a picture of the rim but as I'm struggling to learn macro photography the pics might be lousy. I did weigh it and it came out at 3.1 grams, which would put it in the correct weight range. Just glad it is real. I guess you never know what will show up at the flea market, most of the time it's guys selling common-date cleaned Morgan dollars for $50 each.
In that condition it is about a $100 coin, though recently I've seen some certified examples of the date sell for much more.
Sean Reynolds
"Keep in mind that most of what passes as numismatic information is no more than tested opinion at best, and marketing blather at worst. However, I try to choose my words carefully, since I know that you guys are always watching." - Joe O'Connor