I looked at both of the numbers you mentioned and they both looked to be the same length.
Where is your pin located in the bed of the truck? Is it directly over the center of the rear axle? Is it mounted forward of the axle? Can you post a picture of your pinbox on the trailer?
See if you can find what you have and what you need here:
https://www.rvupgradestore.com/v/vsp...ationGuide.pdf