Sharing printers with Gutenprint

We’re on 10.5.7 and I am trying to manage printers through workgroup manager. It goes something like this.
Mac Server adds HP printer via IP address (they’re all old school HP 4 and 4 pluses). The only way I can get them to print without gibberish for output is using the Gutenprint drivers- the standard hp drivers don’t work.

Now, when I add those printers to a group’s printer preference through WGM, the printer refuses to show up when they log in. I think it has something to do with using the Gutenprint drivers, since other printers not using the Gutenprint driver show up when added through WGM. This includes the same HP printers when I use the non-functional HP driver.

We have server support, but the Apple people are not sure what is going on and since it’s an HP printer, they’re meh about digging in. Any ideas?