what to do with a Sierra wood stove installed in 1983?

I have a Sierra brand hearthstove, the model is a Classic Turbo Burn 1000t that was installed into a pre existing fireplace in 1983. It was used regularly until 2008 when my father passed on. Since then, it has been brought to our attention that the installation of the stove is not up to the current code that is required. Though it was installed properly and professionally in '83, now it is not up to code(burns too hot for the chimney, is what we were told).
My mother is reluctant about the safety issue now, and we decided that if there is not an easy fix to make it right, then we would rather just get rid of the stove, to at least get use of the fireplace behind it.
Was curious if anyone knows if there is a market for a used wood stove like this? I hate to get rid of this stove, it served our family well for almost 25 years, and safely too, never an issue. I have had it on Craigslist, and it has not generated much interest.
Would appreciate any comments or information that might be helpful in this situation, thanks all!

Have you looked at the flue outlet? Maybe it would be easy to slap a liner in there, to the top of the chimney.
Yeah, those old inefficient stoves are a dime a dozen on CL. Might be OK in a garage or something but not for anyone serious about heating with wood.

Looks like a rugged one and big.
I bet it did a great job for your family!
What are the two big knobs on the right side?