Just a word of causion if you plan on buying from an unknow source... ie. a teardown of a tank from someone online whom you do not know.
I would be asking yourself and them... why are they selling there LR?, have they every treated the tank with chemicals?, if the system is already down has the LR been properly stored to keep it LIVE?.... etc....
If you feel confident in there respons and you seen the LR in person and all looks good then, hey... if the price is right!