It does come with the full-length tube, as you said.Pretty sure it comes with the longer extension and it's been prebuilt for the max allowable under our gun laws.
The only thing it looks like it could use is a clamp between the barrel and the tube to beef it up a bit in case of a slip and bump in the field.
Anyone know what material the heat shield is made from?
The heat shield... I would say it must be an aluminum alloy.