Beautiful 80s Valentino dress- real or home sewn??

That's a nice find! We cannot authenticate items here, however, Valentino Boutique is a ready to wear line, so not the same as couture, so I don't see overlock stitching as out of place. Is the fabric stretchy? In that case the, overlocking makes sense (and that may also be why it wasn't lined). As far as I know, the designer sewing patterns, which are usually by Vogue (and they have done Valentino too in the past), never came with a label with the designer's name. What you could get was a Vogue label, that said "Vogue Original de Paris" for example. Also, those didn't come with a size tag . So the label, if it wasn't original to this dress, could only have come from another garment. It's hard to see the stitching in your photo - I can't say if that's original or not. I own a Valentino Boutique item with the same label and same type of size tag, and it also has a care label and the Made in Italy label. Maybe your dress had them and they were removed? Is that a little bit of loose stitching to the right of the label in you photo? Might something else have been attached there?