There were or are 2 styles of drive shafts, one with a steel flange like you have and another with aluminum. The aluminum is thicker and longer bolts were sent out for it. Suspect you have the longer bolts for the aluminum flange drive shaft.
I ended up with 4 different drive shafts until they got the correct IRS and length one to me and I have had both styles. They also sent out a revised instruction with new bolt torque values by email.
David W