610 is the most widely available latest update. Some are getting 9xx versions, but have verified for myself in FDRS that my truck doesn't have that update available yet. FDRS doesn't identify updates, so lists and names wont do you any good.
Be sure to tell them to do all updates on the Gateway Module as well. Most dealers are too incompetent to know the dependency between the 2. They'll see a pending GWM update but no APIM update and proceed to tell you the APIM is up to date.
I was stuck on 134 until I bought a cable and did it myself after 2 unsuccessful attempts to get my dealer to do it..