The S&S instructions for replacing the drive gear (Instruction 510-0319) says in item 13, "We recommend installing belt cover spacer kit (500-0257) if not already installed."
If you do a Google search for, "S&S X Wedge cam belt failure" you will find there are lots of forums listing many cam belt failures up until 2014 when the upgrade came in.
Although your cover venting holes will possibly do the job, I would be tempted to refit the spacer washers as well. Later modified covers have extra venting holes but still fit the spacers.
