88 K3500 Control Arm Confusion.

[sammygunns]

So Ive had this backyard project going on for most of summer, I got to the point where I needed new upper control arm bushings and I figured I'd just buy the whole arm with ball joint. I bought some Moog RK620629 and RK620630 control arms. Went to put them in and everything lined up except for the ball joint, the stud is too big to fit into the hub. Moog states these arms are for 88-98 trucks. Would it be because my truck is an early 88? I just want to know why these ones dont work. Any info is highly appreciated

88 k3500
454
SRW