Couple things...
I wouldn't buy this as a collector; were I to buy it, I'd buy it as a shooter. The stock and gas cylinder make it pretty obvious it's no collector's piece.
Check on the bottom of the barrel, from the bayonet lug on back to the reciever, where the cut in the handguard is. See if that's stamped with anything (like, BLUE SKY). This means it was re-imported, and loses a bunch of value as a collector's piece right there, too. Check for other markings on the barrel as well (VAR barrel? etc)...
For a shooter-grade, other than checking the other parts to make sure they're mil-spec/mil-surplus/military, it's good to go...but, a bit overpriced. You can get good shooter-grade Garands from the CMP for that price, and unlike that one, it's value will go up with the pedigree of the CMP papers to prove it. (This dosen't so much apply to the Danish re-imports, but CMP papers are CMP papers, and they'll still get a sliver more than a non-CMP gun.)
I'll admit, it's definitily unique-looking, but is it really worth $500 to have what, in my opinion (just that, opinion, as a collector :) ), is a Goofy Garand :)
As far as re-bluing goes...yes, the barrels were parked, on military barrels. This includes the Danish and Baretta barrels...(as far as I know). It almost looks like (from the barrel, etc) like a one-off customized piece that someone decided they wanted to dress up, like those silly gold-inlayed AR15's and other things the Franklin Mint or whatever distributes...
None of this is probably any help :)