Do you have UL certified load cells?

No, because UL certification for a load cell is not necessary.

UL regulations refer to the safety of electronic instruments. The mark indicates that the instrument has been tested to ensure that the user does not get electrocuted or receive an electric shock.

However, UL considers load cells to be an ultra-low voltage device (less than 50 VAC or 75 VDC) with very low current, so the risk of electrocution is de facto non-existent.