The lp subsystem originated either in System III or System V, I can't remember which. But it was intended to control printers that were directly attached to the unix computer.

The BSD guys invented their own spooler. It could control directly attached printers and it could send a request over a network to another computer.

The USG package has an option for multiple copies and the BSD package does not. And the BSD remote printer protocol does not have a way to send a copies paramter over the network.

Vendors like Sun throw these packages together and maybe toss in a few more goodies.

I'm guessing that you are sending print requests over the network and your lp package knows this so it's disabling that copies parameter.

Rather than fiddling around with the lp subsystem, I would write a script called lp and put it in /usr/local/bin. People who need a copies parameter will put /usr/local/bin first in their PATH. The local version of lp will just handle the copies by creating a long file with several copies of the input and then send that file to the real lp command.

By the way, I think that model script gets copied to the interfaces subdirectory and is given the same name as the printer.