The washers were used at one time, but I don't think the factory used them after 1978.
But it's hard to say that somewhere along the way, that they may have been installed by some unknowledgeable individual.
The problem with the washers, and I don't know if they were the split lock washers, or just 'wave' washers that BMW is fond of using, was that they would break, fall out, and then the bolt was loose .
I have the original bolts and have reused them numerous times, and have not have a problem .
They are a pain to properly torque, I have a Snap-On tool called a torque adapter, looks like a 12 point box end wrench about 2 inches long, with a 3/8th's inch drive square hole at the other end .
Use a torque wrench and tighten to the specified torque, and 28 years later, no problems.
The Snap-On part number is : FRDHM10.
I got mine in 1984, and I paid about $10 for it, I havn't checked lately, but I think t is in the $25-30 range today.