I've used hallertau hersbrucker in pale ales, IPA, blonde and golden ales... Its an aroma hop mostly used in German lagers, but I like it in pale coloured ales, added in last 10 to 5 minutes of boiling.
With low alpha acids and low cohumulone, it exhibits a pleasant aroma with a balanced, fruity, spicy and floral character. It has commonly been used in German lagers, however this variety is now making its way into some fine English cask ales.
If they are labelled just Hallertau, they could well be the American grown noble hop from Yakimachiefhops. If they are of German origin, as pointed out, the Hallertau general denotes that they are from the Hallertau region and will be accompanied by a variety name. Any indication of the country of origin? Also the Alpha Acid value may indicate what variety they are.