BTW, in almost all things aside from the bayonet type....when you hear/see the word paratrooper it generally matters not, the stocks are all the same length, the only thing changed was the length of the barrel, which...in turn changed the length of the bayonet.
If you are concerned though, a spike bayonet 'paratrooper' stock, MIGHT have the second reinforcement pin cut into to widen the path for the fatter cut down stubs for bayonets they used. If the seller indeed pulled it from a paratrooper....more oft than not folks just add that on because the paratrooper modified guns get more money. Folks will say paratrooper on things that are absolutely not related to the modification.
The use of paratrooper towards anything SKS is actually laughable...they didn't exist until US importation sort of 'demanded' it.