I want to see if a company that claims to be a CMMI level actually earned it. Can you help?

Yes. If the company that claims to be a CMMI level asked the CMMI Institute to publish its results in the PARS database, you will find it listed there. The appraised company should also have an Appraisal Disclosure Statement (ADS) that describes not only the appraisal results, but which part of the organization was appraised.