here's a clip of Tobias Capwell (Curator at the Wallace collection) talking about two modern reproduction swords.https://www.youtube.com/watch?v=vi8BafTnQKA
Note that he's using the term "real sword" in regards to historic pieces, which I wouldn't necessarily agree with ("authentic" is the word I'd use, since a reproduction sword is still a "real" sword in my book, as long as it's not a prop).
I guess the only caveat, when it comes to reproductions, is that authentic, museum pieces, are guaranteed to have the correct dimensions and balance, which not all reproductions have.
Take reenactment weapons (using the term "weapon" loosely) for example. What we do, is a performance - full contact stage fight if you will.
What we call "practical" swords, are made for impact, rather than cutting. And because they are blunt, the blade is heavier (that's why historically, practice longswords were narrow - to keep the weight down despite having a thicker, blunt edge). If you make a sword with the correct blade length, and width, but a 2mm thick edge, you either have to make the fuller excessive (which gives you a weird shape), or it's going to be heavier, and then you have to make the pommel and guard heavier (usually by making them thicker), and that makes the sword heavier again (a reenactment sword can put on up to 300 grams in this way if you want to keep the balance correct).
Another problem, especially with viking period reproduction swords, is that they tend to have oversized grips (i'll explain that in the next post).
Bottom line is, that however archaic, a modern sword is still a "real" weapon. Only problem is that since they're not used anymore, outside of reenactment and practice, we have forgotten how to make them "the right way" (but we're getting better at it).