The problem you will have is without specifying a specific Copper Alloy as in 101, 102, 110, 122, 145 etc. you will have a hard time finding or having copper nuts and bolts made let alone off the shelf. Hard Drawn or Soft Drawn and the list goes on. Generally for electrical work most applications or designs lean toward the use of brass as brass nuts, bolts and washers (flat and locking) are readily available from suppliers like McMaster Carr Supply.
Just my take...
Ron