I definitely think it's worth trying...
a 600k up limit should be lag free for up to 10 players. You might want to increase this to 12 or 14 and ask your players to see how it's handling.
At 12 or 14 players I think your 866 will do fine provided you turn off any unneeded programs and nix any TSR's. (if you CTRL-ALT-DEL to the taskmanager I would hope to see 25 processes or less running on that machine, with the only major application being SWBF2). Without rendering etc I think that pc would do fine.
in Taskmanager you can also set the CPU priority for the BattlefrontII.exe to "above normal". I do this on my server which doubles as the lesser of 3 household pc's (email, surfing, print server) and I haven't encountered any stability issues that I don't encounter with the process set at "normal" priority, and this makes sure that even thought the program is running in the background it always gets full cpu priority.
Looking for SWBF2 Server related resources?