Neil,
I am afraid that the interior fittings to the helmet are somebody's afterthought.
1. The cork spacers, if indeed they are cork, are far too large
2. The "webbing" strips with a drawstring is totally wrong.
3. I am not at all sure that the puggaree is also not a later addition, with only four pleats it doesn't look right for the period.
4. The collet to the interior should be a 4 or 8 spoke cartwheel
Is the binding around the brim leather or cotton drill? An officer's helmet should have the former and an OR's the latter.
You are right about the WD marks as they cannot be made out from the photos, so I can't give an opinion on them.
I also note that the interior hooks for the chinstrap are missing.
I attach photos of the two interiors - OR's and officers.
Stuart

- 8 cork spacers.jpg (116.19 KiB) Viewed 1217 times

- Colonial Officers interior.jpg (180.01 KiB) Viewed 1217 times