Are GT18 parts interchangeable with SS18 parts?

As the title implies...I have an SS18 and found someone who's selling a non-running GT18. She has a number of attachments, including a mower deck which I need. I haven't gone to look yet (it's a ways away) but I am assuming it's an Onan 18 and the pics I have seen look very similar to my tractor. Are these tractor engines the same or did they change between the SS and GT years? Also, will the mower deck and other 3-point implements work on my SS18? Any information would be greatly appreciated.

WHETHER YOU ARE TALKING ABOUT TRACTOR PARTS OR ATTACHMENTS. ALL THE EQUIPMENT WAS CATEGORY O NO MATTER WHO MANUFACTURED IT. THE SS18 & GT18 WERE BASICALY THE SAME. I HAVE BOTH AND I THINK THE BASIC DIFFERENCE IS THE GT18 HAS A PLASTIC DASH THAT IS VERY EASY TO BREAK.

Thanks for the input, I was able to get the model number of the unit for sale and then hunted down the manual and compared to mine. The two Onan engines are slightly different, but the carb, points, intake, etc..the transmission is the same, front end, wheels, etc...Now it just up to price. Thanks again.