I don't have the instructions any more but from memory this sounds like it relates to the twin .303 machine gun mount on the bonnet which is an alternative to the smooth one but will need to be without the glazing. There are also 2 options for the pillar mounted MG and the canvas top. I built the airborne version and some of the options were not listed in the instructions and I am not sure if the omissions are the same in both sets.
As toweathering in the footwells - a dark earth or black wash is good for getting grime into the corners or weathering pigments (which need a spray varnish) are good for general grubbyness - though the limited space in the jeep will make this awkward.
From what I saw when I looked at the online instructions for the airborne kit they seem to be the same instructions.
for the weathering I think a wash would probably be easier then so I can use enamel thinners to wipe away any unwantEd excess. I’ll dig around and see if I have any for the job.
thanks for the advice.