Altec never made a crossover by that model number, AFAIK. That's the first GPA 604 network AFAIK.
I'm gonna guess you're asking about a 604-8G/Stonehenge III/model 17(33315) network like you have pictured. Sorry, that's one network i don't have anything on. They're so short of what a 604 really needs, i don't think most folks even bother with them.
EDIT: did a little sleuthing and it's surprising to find an absence of a circuit drawing with component values for these networks. I wonder if they aren't essentially an N1500 with component values scaled for ~8ohm drivers??????
FWIW, these are N604-8A:
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