From my previous experience with a wrong part in ROTF Scout Ransack, it's not worth the trouble trying to return to Hasbro. So I plan to return to Target and just explain it's defective. Thankfully I'm pretty sure there are a couple left in stock at one of the Targets near me. Of course, they'll probably get confused because when I bought this, it was listed under the DCPI number on the Target website (087-06-1666), but last time I went into the store, they had it listed under the regular DOTM Human Alliance DCPI (087-06-2312). No idea why the change.

The missing part can also be seen here in this video by Optibotimus (he calls it a doo-dad):
http://www.youtube.com/watch?feature=player_detailpage&v=LJzi-BI4Qrc#t=666s
And in this video by Peaugh:
http://www.youtube.com/watch?feature=player_detailpage&v=82mFlGTLUNo#t=369s