Buy them and keep it until you can sell it to old-school equipment collectors, last time i saw a woofer with square magnets was the woofers in the vintage Advent Model 1 home speakers, and they were from the 70s.
As far as performance the current offerings would run circles around these old-school woofers, they have limited excursion capability and usually foam surround that rots, none of them can take more than a few hundred watts and they usually don't sound very good when you play really low bass notes.
Those are best kept on a display shelf or a very moderate car/home audio install.
