Yes it is True the Dubiels were the O.P. (original pollocks).
Dubiel is pronounced roughly "DOOB-yell." As of 1990 there were 8,722 Poles by that name, living all over Poland, with somewhat larger numbers in the southern part of the country. Polish experts say that it comes from the archaic noun _dubiel_, a term meaning "simpleton" but also "a kind of fish, Carpio collari." A connection with _dub_, the Ukrainian word for "oak," is also possible. Without more information it is impossible to say which meaning applied when people first started calling an ancestor by this name. Perhaps he was a simpleton, perhaps he was somehow associated with that fish, or perhaps he was the oak guy. Only research into the family history is likely to clarify that.