Sorry, but I don't think so.
We just saw Spectromagic on Tuesday night, and we got to Magic Kingdom at 7:45, and ALL "curbs" were taken. We were second row, on the curb in front of the big candy store.
Now, this may have been because this was the only Spectromagic parade during the whole week we were there. (I think).
Maybe when it runs more frequently, it's easier to get a spot.
But for us, 1 hour and 15 minutes early was not early enough to get on the curb.
Hope this helps.