Class C built in propane tank.

Manchester LP tanks in Bedford Indiana appears to make a variety of tanks for the RV industry. I would contact them for advice and replacement. Buying used may be OK but you may be buying an even older tank that has been refurbushed. I just took my tank off to have a new shutoff valve installed. My reearch said to let a professional do it, so I did. Empty LP tanks are apparently way more dangerous then those with actual gas in them The fumes are what can ignite. They replaced valve and pressure tested all the other connections. Got to love small towns, they charged me $38 for tha valve and no charge on the labor. I also had 3 twenty pound BBQ tanks refilled, total cost for everything was $88. I then wire brushed it, repainted it and reinstalled it. So my advice is to remove, have it checked and then make an informed decision if the tank is safe or not. I would bet that it is cosmetic rather then structural problems.