Heres how it works:
If your bottom bracket tube (the tube that is part of the frame, aka BB shell) is 73mm wide, then you only need one spacer on the drive side. If your bottom bracket tube is 68mm wide, then you need two spacers on the drive side and one on the non-drive side.
If you are using an E-type (BB mount) front derailleur, then that drive side spacer goes away and you install your front der. there.
You can measure the tube width with any calipers, or maybe even a tape measure, then convert to MM by dividing the inch measurement by 25.4.
thats it in a nut shell.
I dont know what specialized's shell widths are, maybe someone can chime up.