Suburban SW10DE hot water tank question

Our RV is now over 10 years old and has been used every season. Last year the water tank fault light would come on occasionally. I discovered resetting the switch would make it work. Then in the fall when I winterized I blew out the combustion chamber and there was a fair bit of rust came out. I suspect the rust was sitting on the burner area and causing the unit not to light. Anyways we use propane almost exclusively on the tank due to other high load electrical devices. My question is how thick is the combustion tube area of a Suburan water tank? Or should I not even be asking and buying and installing a new one without question? I plan to get a new one without the 110V option as we never use it anyways. Can that cause any install issues? I plan to swap a SW10DE with a SW10D. Thanks for any assistance.