Save yourself the trouble and buy the right one - Accumulator.
But that aside, if you search around on SCCOA (like I did) you'll find a couple different part #'s. Some people have said that ones which were supposed to fit, didn't, so keep that in mind. Sorry, I don't have any specific part #'s to look for but in most cases you'd be getting an old stock unit rather than a new one since this braking system has been basically out of production for a long time.