Sales Header Custom Fields

Just looking to confirm, are these sales header fields available to use as needed for any custom needs we choose?:

cust_field_1 (through 5)
cust_date_1  (through 5)
cust_number_1 (through 5)
cust_decimal_1 (through 5)
cust_short_text_1 (through 12)
cust_long_text_1 (through 3)

Thanks,
Doug