not sure if my LO had hiccups earlier (28 weeks). it was tiny and rhythmic and regular, and it felt almost as if I had trapped a pulse between my belly and thigh, if that makes sense! it didn't last long either.
Yes, it sounds like hiccups to me. The first time it happened to me I freaked out, thinking baby was having some kind of fit. She used to get them nearly every night, so I got used to the rhythmic pulsings after a while.