At programming level, in both cases, it is not very complicated ... It is sure that if you only add variables and conditions for your VN it will go very quickly.
But as in most cases people add score window, menu system with phone in their vn, in the end the gap is very short between the two.
Not to mention the fact that in a lot of cases (all?) sandbox are just VNs hidden under a pile of grind and false liberty.
In fact we could take a good part of the sandboxes that we find here and make a VN version of it without changing anything in the story or in the order of the scenes.
But instead of having to look for a scene that will happen somewhere without you being notified, we would just tell you to choose between places as a choice, possibly giving you a clue about what can happen there.
What we find with maps and icons of destinations etc ... are just choices in another form.
So finally, is there really a difference?
I rather believe that the difference lies in the writing (a little in the graphics too). VNs containing more text and dialogs (sometimes boring) and sandboxes rather short and responsive things (sometimes without depth).
But I will stop there otherwise I will start to talk about games that manage to take the worst of the two options to claim that they have content ...
But to answer the subject itself....
Yes.