You are indeed correct about the orientation of the pin; it does go in from the front of the axle, however, the hole and pin are parallel [it is the groove that is tapered], so can be fitted from either side of the axle. If you find it cannot fit one way around, it is no doubt because the torque that has been applied to the spring washer under the domed nut in the previous installation has deformed that end of the hole. My take on this issue, respectfully, Brian