☑ no chain of custody documented
☑ result not published
☑ laboratory NDA upheld
If I was a conspiracy theorist, I'd suspect a coverup, but since I'm not, I simply suspect...
More importantly, most reputable labs in the US would adhere to NAGPRA and only perform tests on indigenous remains IF it is clear they were obtained in a professional manor with consent of the indigenous population that may related to the remains. Very old remains, such as Kennewick Man can create a bit of a grey area with arguments from both sides, but in general if there is the possibility of looting and/or postmortem assemblage (Gaff making) involved, no one is going to touch it.
Mexico and Peru may have different standards, but as you point out with no provenance, no peer review of the results and a commercial NDA, it's largely useless. The test could have been performed on anything from a 1000 years ago.