Welcome to the TechForum tboon! I do not see any indication in the datasheet that these are calibratable in terms of NIST standards. These are probes for equipment. Typically, calibration applies to specific measuring equipment. You can refer to this Forum post for more information about Calibration Certificates: Certificate of Calibration - Site Help, Information and Feedback / Supplier Documentation - DigiKey TechForum - An Electronic Component and Engineering Solution Forum
Omega does offer some calibration services, this link leads to their calibration page: click here. I would advise reading over the information on that page.
EDIT: I missed a detail in the datasheet, please see the response below.