You've certainly helped with the weight, but you will put more load on the beams. Cat rigged you will probably be ok as long as your beams are in good condition. Just don't go beating too many Taipans or Hobies!

The other area you can usually save a lot of weight on older boats is by removing most of the fittings! It's surprising how little you really need compared to the way they were rigged 15 or more years ago.