I just bought a pack of 25, 10mm copper crush washers from McMaster Carr. Cost was $7.61 + $4.39 shipping, total of $12.00. McMaster P/N is 97725A200 for 25.
If you are going to do brake work and remove the lines, these should be replaced.
The items I received looked identical to what is used on bike.
I counted 23 of these washers on my 1st gen.
The price at partshark.com was $1.38 each + shipping. Total for 23 would be $31.74 before shipping cost
Part # is WASHER,PLATE - 90201-10118-00
Same part # is used on 1st & 2nd gens.
Gary