By stand alone I think they mean that the printer is simply directly connected to a local computer. The printer does not have a NIC installed.
But it is possible. Let say you have a PC that is not a member of the domain and you want to publish it's printer in Active Directory.
First this computer must be on the network. Second the computer must be shared and available to everyone.
I will assume you have another server that is your print server for network connected printers. On this server you need to map another LPT port to the stand alone computers printer. On the server make sure you have an LPT2 port if not add it.
Add a local printer with the correct driver for the stand alone printer. (It does not matter that it is not connected to LPT2 right now, we are going to fix that next.) Share it like you would any other printer on this server.
Run the following command on the server:
net use lpt2: \\standalonepc\sharename /persistent:yes
What this does is redirect any print jobs that the server receives for LPT2 to the shared printer on your stand alone printer.