How much wood, if any was used in Nordic heats around the 2005 year model? If so would this be a problem with them now?

2005 Nordic was still using wood. They used Greenwood industries XL treated wood which is really rot resistant. However if the boat was left out in the weather uncovered for years it could be a problem. I've never seen a Nordic with rot, but that could be because people generally take good care of them.

What year did they stop using wood? Would similar boats have been the same also?

2007 If I remember correctly. Not sure about other manufacturers.