The switch has redundant, load-sharing power supplies numbered either 0 or 1. You can display details, including the PS's FRU number, by displaying details for each PS.
-> show -d properties /SYS/PSslot
where slot is either 0 or 1, corresponding to the PS for which you want to display information.
For example, to display the details for PS 0.
-> show -d properties /SYS/PS0 /SYS/PS0 Properties: type = Power Supply ipmi_name = PS0 fru_manufacturer = Delta Electronics fru_part_number = 7065505-01 fru_serial_number = C94928 fault_state = OK clear_fault_action = (none) ->