ATF: Big Country - Type of BC Lippert Pinbox

[Theresau]

We are investigating installing a TrailAir TriGlide pin box on our new 2014 BC (still in transit).

Per the Standards spec, it has an extended pin. Is it a 1621 or 1621HD?

 

[Theresau]

We now have the serial # for our BC's pin box. It is 028-000159006. What model of pin box is this?