That spring is kinda important, yeah... Also you could do the same spring placement that I did, which was copied off of Brandon's rebuild thread...
all of the red and white springs I put into the accumulators for 1-2 and 2-3, saved all of the yellow for the 3-4 when I get to it. Also might want to clean up the piston bores with a scotch-brite pad, if you haven't already... helps with preventing chatter after reassembly.
Good luck with the search, I think I might be able to get you one if you can't find one.
