[snowbirds R us]

I am looking to find out if my '08 2400rl has a lippert 1621 or 1116 pin box. I have a chance to pick up a TrailAir Air Ride 21K from the local Craigslist. 21K seems to be a little overkill but there is a Moryde 19k on the rig now. Is there anyone on here that can provide some insight to this? I am pretty sure I have the 1116 Lippert but don't know for sure.