Maybe contact the reseller and offer 5 bucks for them to send you one. They can take it off another workstation and still leave one of the two that usually are attached to the back of each workstation outside, up by the power supply.
Even more secure..... there are matching tabs at the back with holes in them so you can use a padlock or combo lock, which in my mind would be better than using the stock key which is the same for all the workstations I have dealt with here.
