Recently picked up an old radial arm saw and need a bit of advice

Manual available here http://www.owwm.com/files/PDF/Dewalt/710RAS.pdf
(neat site over all)

the arbor is missing the two spacer washers
The ones I am referring to the pair shown on the bottom right of page 3
of the pdf, or # 13 on pg 27

So would those spacers be common enough to get elsewhere, would a stack
of normal flat washers work?
I haven't asked dewalt yet because I am not expecting much service on
something that has been out of their line
up for so long.
Thanks for your help