Company background checking
How to check is this org OK or not?
It really depends on what kind of investigation you are looking to perform. You could check if this company exists by looking up Secretary of State records. You could also see if its in Good Standing or not.
However, to check the internal structure of this company, or whether it has any liabilities, you would need to use the help of anattorney and/or an accountant who would go over the company documents and assist you in all the necessary amendments to the company structure to add yourself as a co-owner.