Hehehe, quite funny to see some people searching excuses when something is not working.
There is no evidence showing ILM modificated the lenght of the neck for that particular shot, even today having this included in the rig would be hard to do.
Scaling a model between shots is done very often, but they scale up or down the all thing, not just the head ... So to me, that's bullsh*t.
As it was posted before there are wireframe version of that pose available and even from other view it looks just fine. So the ILM model was good from a large angle not just one.
People managed to make a model in that pose looking good from every angle in the past and will do in the futur (but no spoiler lol). So that's not impossible.
About scan, yes, the head looks like the 1/5 model, but ILM modifiacted the head of their scan data for the first film so a perfect scan of the 1/5 maquette does not reflect the actual model from the film.
For the rest of the body I doubt it's a scan, I can be wrong and I'll bring more evidence if I'm forced to but it doesn't look like the 1/5 to me, specially the skin details, and proportions looks off too, that tibia seems very long here. Feet looks very similar to the JW base model from ILM ( check the making of)...
Carefull Fu_Manchu last time I checked ( about Chronicles using first generation cast given directly by Legacy ...) it happend to be a massive hoax ...
Now you say it's a scan from the full body 1/5, could be very easy for people here to compare with chronicles 1/5 pictures and see if the wrinkles matche or not ... I'll let people do the job, it's very easy to check.
A 3d scan can mimic every single details, my nexengine scanner can scan 0.01 mm and I bought it 7 or 8 years ago, I even got back the scales on the horizon dilophosaur, so let s talk about a 1/5 TRex lol...
Horizon models are all made from SWS maquettes, they may have lose a bit of volume but nothing crazy. It s written on the box and most of the JP fans know that ...
And talking about papo first it s not 10USD but even if it s crazy cheap compare to other licenced products they managed to get it right, so big respect to them
... I actually love papo, their models are awesome.