Wally, yes, they should be straight arms on the mule drive. (i believe that's what you mean when you say hangers) And no, a mule drive from a NF will not fit a WF. Actually, the front of the mule drive, the hanger assembly, from a NF will not fit a WF. A good pic of the mule drive you need can be found on the cub cadet website, parts lookup. You're looking for the hitch quick attachment for a 149 models numbered 400,001 to 529,999. That will give you a good idea what you need. I included a link, but not sure if it will save the info for you to view it.
http://www.cubcadet.com/webapp/wcs/s...A/040075600006