Hi there. I've had an ID here for a while, but haven't been compelled to post anything yet.
As to your question, some high-end saltwater reels have a 'sealed' drag system, with a rubber washer that keeps the brine out of your gears. However, I have fished many, many hours in saltwater with gear that was only ever intended for fresh. Mind you, I was very meticulous about cleaning my gear after each use, and I used a lubricant that was saltwater repellent. I would assume that you are asking because you will be doing some fishing in the salt. If this is the case, I would just use the gear that you've got, and clean it thoroughly the same day that you use it.