Hello guys i picked up this axle this weekend and the guy i bought it off said it was an 83 but i dont think it is. i think its off and earlier model pu since it dosent have the reinforcement truss on the bottom any ideas?

 

looks like a 79-80 axle since it has no truss
81-83 had a short truss
84-85 has the longer truss

 

Thanks man kinda figured