Yes, the photo in the Truck Shop Manual shows lock washers in the illustration but (as noted by jorb) on the next page advises to "NOTE: Use new lock plates under cap screws and bends tangs up to lock cap screws after assembly."
If you have ever seen the inside of a torque-tube u-joint bell after a supposedly properly-torqued cap-crews is used without a properly tanged lock plate, you'd use a lock plate (any maybe overkill with LOCTITE).
I (and my professional friends) have unsuccessfully tried to use a torque-wrench (various sizes) on the cap screws on these u-joint assembles; but, the technique from jorb's two pros, using lock-plates, keeps me from having bad dreams about the u-joint coming loose (I have had such dreams over the years).
