Normally if the fire pump controller is UL and / or FM approved there will be stickers to this effect somewhere in the cabinet. In order to be allowed to place these stickers in the cabinet, the manufacturer has to go through a lengthy test and verification process including witness testing by these organizations. Afterwards, during the production process, the manufacturers are subject to periodic (typically every 3 - 6 months) inspections to verify that they are building what has been documented and approved.
If you are looking for proof above and beyond this, you could try contacting either the manufacturer or UL and FM directly and give them the model information.
Note in certain installations and under certain circumstances, it is NOT required to have UL and or FM approval. In which case, the controllers may not be marked as such, but are most likely the same as ones that are approved.
Out of curiosity, what manufacturer and model are you referring to in this case and what is giving you cause for concern?