1990 Ski Nautique

My wife and I just purchased a clean '90 model Nautique and I noticed the floor shows a little flex right in front of the observer seat and to the left of the engine hatch. (I think this is where wetsuits and gear came off and eventually made it's way to the marine grade plywood.) The boat only has a little over 800 hours on it and I was wondering how difficult floor replacement is and if I should be concerned with the stringers as well? The rest of the floor feels solid as a rock and every square inch of the boat has been kept in near showroom condition. (it came out of a dry climate in Southern Califrnia) Any advise or words of wisdom would be appreciated. - Thx