the 3 in the vin means mexico the W is Wolfsburg and for us MKI owners 1 means US. I believe on the MKIVs and MKIIIs there is also a B or something for the brazilian plant on some golfs
I know for sure they are made down here in Mexico, as well as Beetles, I've personally visited the factory in Puebla and seen them being loaded in trains and trucks for domestic and exportation.