The way I read it, then the prototypes does not exist in solo play. Even if you went to the right station, it wouldn't be for sale, unless you are in open mode.
Also, if you log out while having this in your cargo, whether it is combat logging or 'legit' logging, the prototype will disappear from your cargo, and you would have to go back to buy another.
Also, my guess is that this particular piece of cargo will not get flagged as 'stolen' if it is taken off the cadaver of a destroyed ship.
At least that would be what makes most sense to me.
Also, if you log out while having this in your cargo, whether it is combat logging or 'legit' logging, the prototype will disappear from your cargo, and you would have to go back to buy another.
Also, my guess is that this particular piece of cargo will not get flagged as 'stolen' if it is taken off the cadaver of a destroyed ship.
At least that would be what makes most sense to me.