I'm not sure when Magnetic Mary Lou dolls came out, but I do remember playing with something similar in the 70's. I held a swap based on the original Magnetic Mary Lou doll, where everyone needed to create three dolls using the "fashions" from the boxed dolls. I provided links to various places, so they could actually see the fashions. I even found a box set being sold somewhere for $70.00.
I didn't get many players, so I created three dolls myself to include for swapping.