I recently purchased an HO GP9 that includes a factory installed decoder.  Its Bachmann, not Spectrum, and is a blue box.  Trying to program it using JMRI, the program asks which decoder it is (It gave several choices based on how many functions the decoder has).  Does anyone know what decoder was used in this model and how many functions it has? 

I see nothing in the instructions that came with the locomotive telling me the model of the decoder or any description whatsoever, other than the term "DCC On Board".  The store clerk told me it is a Bachmann decoder, as opposed to another manufacturer's.  Are there not any instructions available on-line to aid in programming the decoder, and if so, where?

Thanks for any assistance you can offer.