My understanding is that the '87 &'88 hulls were the heaviest of all the hulls because of overcorrection of the problem redline hulls. So that tells me that these hulls could be between 117-120lbs each.
Ok....but simply throwing the hulls on a scale would be a much more accurate way of determining hull weight than trying to figure it out by manufacture year. There have and always will be some amount of variability in hull weight regardless of production year. Also, IMO, especially if you aren't racing, I'd choose the slightly heavier but stronger hulls every time over the light ones.
FYI, my 1990 boat has the dagger trunk with only one seam, so it looks like this was likely introduced in the 1989/1990 time frame.