Just before they went poof, Magistroni apparently produced some 6 sets of a new crankset as part of their last gasp - the Super Zenith "gruppo" (headset, bottom bracket, crankset). The cranks themselves were steel, with a press-fit alloy 5-arm spider and alloy chainwheels mounted with 5mm allen bolts. Apparently several of these cranksets made it over to Spence Wolf at Cupertino Bike Shop, and into the hands of riders from the San Francisco bay area.
The bottom bracket spindle was round, like a cottered spindle, but with a flat taper on one side, and the crankarms were attached with 6mm self-extracting allen head bolts threaded into the spindle, and held in place by rings threaded into the crankarm, which were removed with the included pin spanner. Well over a decade later, self-extracting bolts were claimed by Shimano as their new innovation... The bottom bracket cups looks basically the same as the "Ni-Krom" bb cups, they just say "Super-Zenith" instead.