Not at the moment, given current bid/ask prices. I think the "floaters" (variable-dividend series that would have low div rates if they were turned back on right now) offer the best value, and the "liquids" (FNMAS/FMCKJ/FNMAT) offer the worst.
In fact, I maintain a model that ranks all 38 pref series (outside of FNMFO) for best buys and sells, with the intent of selling the top sells to buy the top buys. This has worked quite well for me in the past.
Occasionally the top 15 lists overlap (FNMAM and FNMAK are on both lists, for example), but that's due to the huge bid/ask spreads the less liquid series tend to have.