Well it looks like SJS screwed up. Surprising to me because you can tell at a glance if it is a NIG AW hub or not; for example the driver splines are a different length.pre-NIG AW; long driver splines, lockwasher on RH coneshort driver splines, no lockwasher on RH cone (in recent years)
FWIW SA didn't "quietly slip NIG hubs into production in the 1990s"; they launched different models which were NIG type or not, and sold them in different markets. They continued to manufacture the pre-NIG AW hub right up until production ceased in Nottingham; I have seen examples of pre-NIG AW hubs with date codes in year 1999/2000. [There are plenty of LBS owners and mechanics who think that SA made a serious mistake in stopping production of the pre-NIG AW; to this day they will happily build a wheel using an old AW hub for a client safe in the knowledge that it is extremely unlikely to get broken and it is easily fixed should it ever occur. ]
The only reason SA started to make NIG hubs at all
was that one of their customers was daft enough to use an AW-based coaster hub as a brake, no, the only brake
on the bikes they built. Never mind that the 'dangerous fault' which means the brake doesn't work properly also means that you won't ever get going in the first place....
If you let a pre NIG hub get out of adjustment and it starts to slip in second
a) to start with it will usually only slip under high pressure, you still get some drive rather than none and
b) simply pulling the gear lever will always give you a gear that allows forward motion at any pedal pressure
It is therefore far less 'dangerous' than (say) a chain that is slack enough to come off, or that might not accomplish a gear change, or that might get itself similarly out of adjustment and fail to provide consistent drive. So that is arguably less 'dangerous' than any
bike using derailleurs, and less 'dangerous' than the majority of other bikes with slack chains. IIRC in Denmark, they let folk ride around with just one brake and that is usually a coaster brake; if the chain gets a bit slack and comes off, no forward motion, and..... no brakes! But apparently that is 'normal'.....
And a hub that signals to you that it is out of adjustment as clearly as possible before
the daftest rider smashes it to bits isn't.