Indentification of frame year needed

[RustMaster87]

I recently picked up an 84 Silverado 4x4 this past weekend. I have spent the past few days going through it and need some help with the cab mounts. The previous owner installed about a 4-5 inch body lift and built it out of whatever he had lying around the garage. From what I can see, it looks like it is an 84 cab on a 73-80 frame. The front frame horns have been butchered to fit the 81-87 bumper. Is it possible to tell by the actual mount on the frame? It looks like the previous owner used both 81-87 and 73-80 components for the bushings. I am trying to order the correct mounts but I just want to make sure I order the correct style. The previous owner was a hack and I would not be surprised if the mounts on there aren't the correct ones.

[4wdriver]

not sure how to tell what year your frame is but in the picture you have posted the original bushing is still in place under what looks like a three inch spacer.i only know because i just removed a three inch body lift from the 78 i bought recently.the original bushings get left in and the body lift goes on top of them.took out the body lift and put in new shorter bolts.

[2tons of fun]

they are the same.