Groove Tube tube biasing question

Does anyone know if the GT tube bias kit will work with my 1974 MM 112-sixty five? http://www.groovetubes.com/product.cfm?P roduct_ID=1711
I was told my amp has fixed bias. Is that correct for my model? And if it does have fixed bias what do you do,put in a matched pair of nos tubes and hope for the best?