I've seen an awful lot of MTRs that did not correspond to the actual materials provided in my day and I generally trust the markings on the material before I trust the information on the MTR.
Regardless, if either of the information marked on the product or shown on the MTR deviated from the specified requirements I would deem it sufficient justification to reject the materials since the material is not in compliance with the requirements of the standard to which it was ordered.
If I was having a good day, I might accept some additional testing to establish the acceptability of the product but depending on where the product is from, that may result in even more bad news.
Recently some A105N flanges were subjected to impact testing at -29 C and failed miserably with the most likely scenario being that they were never normalized even though the markings and the MTRs said they were.
