What year did the bigger gas tank happen?

I had a 75 or 76 which I got from a friend in 79 and ran until 85 when I sold it for what I had paid for it. It was so long ago that the boat had a head in that flushed straight to the ocean, no holding tank. It had the saddle tanks which held about 15 gals each as I recall. I'm looking at an 85 right now from the guy who bought it new and it has the 60 gal tank built into the hull. When did they make this change and are there any worry's with this tank? Thanks for the help.