Thanks! It's kinda hard to see 'cause my pictures suck, but Brawl has hands too. I cut some hand details from a Mini-con and glued them onto the appropriate place on the arms.
Indeed, they were like this in the show, at least occassionally. From what I could tell, Brawl had two different kinds of arms in the show. The style I did, and sometimes they were drawn as just generic rectangular robot arms.