I personaly doubt it, but there is quite a bit of evidence that shows both ways.

FOR:
-Obviously the number reoccurence that Dave pointed out
-Hurley knows about most to all the major events (i.e.. Hatch, food) excluding the recent Henrey Gale events
-We didn't know anything about the other losties that survived in the tail end of the plane until after Hurley talked to the black women and her telling him that her husband was in the tail and he survived..
-Hurley could have built the Losties based on his run-ins with them
-Cant think of any more

AGAINST:
-Henry Gale, Hurley as we know it has no knowledge
-Run in with the others (numerous occasions)
-Deaths of fellow Losties (i.e.. Boone, his sister)
-monster on the isle and Ecko running in with it.

So my theory staes that there is no way this is Hurley's dream, because there is way too much that has happend in the coasrse of time and everthing is too tightly linked together for Hurley to just dream up.