When in the 90's? if pre '95 then possibly as they were designed for <80mm travel, '95 and beyond you should be OK, would also look at your headset, it is much easier to find a 1" 1/8th fork than 1", although they are around if you look.

For weight, this will depend on the fork, if full carbon, should be lighter than a steel fork, if a carbon / alu mix, then probably the same, either should be lighter than a suspension fork.