Admittedly it's up to the language whether those two types should be considered identical or not, but there's nothing wrong with considering them unequal.
Yes, as long as there is a particular intent behind each structure even if their “form” is the same. Simply giving different names (to the structures themselves and, especially, to their respective fields) might hint to that. (The field names, in particular, should be considered part of the “interface,” actually.)
