Pochette Bag Chain

I just bought a vintage pochette accessoires!! I love it, but I wanted to kind of dress it up and add a chain to it + the longer shoulder strap (kind of like the new version). Ive seen people post about 3rd party strap options, but I wanted to keep the cohesiveness and get the LV branded chain (bc it has stamping on the clips) and strap. Does anyone know if I can simply go in and ask to purchase the straps? Or how can I find the straps? Thanks!!