Vintage Mandarina Duck bag

Very cool (vintage?) black Mandarina Duck handbag/crossbody. Great burnished silver 'hardware'. There is a long crossbody strap which is adjustable, but I've had to use a little tiny hex key to do it! (I can include it if you want.) Can this be normal? Who knows? Bizarre. Maybe I'm missing some key design feature. Anyhoo, it's a pretty great bag. I've seen other similar bags advertised as leather but I don't like to make that claim unless I'm 100% sure, and I can't find any tags that tell the tale. Last few photos show the very minor 'scratching' throughout, and some wear marks on the side, but overall the bag is in very good condition. Measurements in photos.