In New York and as far as I know in other states vehicles must have equipment on that it left the factory with.

A 1935 Auto with no side view mirror passes state inspection.

A 1950 Auto has factory optional directionals they must work to pass state inspection.

Same model 1950 Auto without the optional directionals will pass inspection. Because that is the way it left the factory.

Same model 1950 Auto without factory optional directionals but aftermarkets were added after the sale by the owner most likely will have to have them operate to pass the state inspection. However if the after market parts were removed during restoration then the Auto would be in it's original stock form.

1968 was the first year seat belts were mandatory by law.

So any Auto left the factory prior to 1968 without the seatbelt option is legal today.

Auto left the factory with just one wiper on the left side is another example. So the key is the Auto just has to be stock as to the year it was made to pass.