The action has been upgraded as well IIRC from one of the airgun mags. AA's website, looks nice, but not a lot of use.
There are two models, looking at the BAR link, so it may be that the OP does have the correct stock, just not the nasty shiny one?
In the good 'ol days it was always a selling point that walnut weighs less than beech. Never seems to get a mention these days.
I've asked a few times for someone to put up the weight of a superlight stock, AA's also, but no response. It actually needs someoene to weigh one rather than go with the maker's figures.
FWIW. My Walnut AA's with one QD stud, weighs 2lb 7oz.
This combination including stock and action weighs in at exactly 6lbs. / 2kgs 700 gms
FYI
Having spoken to an Airarms adviser today , I can confirm they have advised me that the F incorporated on the side of the action refers to the latest and upgraded action and not particularly connected to the superlite series.
Cheers Ian