Long answer, aluminium forks have gained a reputation for being stiffer than steel forks, and therefore giving a "harsh" ride. As with any such objective description, it depends on many variables, such as the fork shape, material(s) used, tubing diameter/thickness/butting, rider preferences and your horoscope.
I can't really see a stiff fork being much of an issue for polo.
Short answer, yes.
Long answer, aluminium forks have gained a reputation for being stiffer than steel forks, and therefore giving a "harsh" ride. As with any such objective description, it depends on many variables, such as the fork shape, material(s) used, tubing diameter/thickness/butting, rider preferences and your horoscope.
I can't really see a stiff fork being much of an issue for polo.