Is it permissible to make a purchase based on a strong presumption that what the buyer desires is present, whether in the specifications or quantity of the commodity, and would that be considered gharar (excessive uncertainty/risk)?

Overriding conjecture in knowing the state of a purchased item is considered equivalent to certain knowledge. It is a fundamental principle in rulings according to Al-Shatibi and Al-Maqqari, and equated with certainty by Ibn Nujaym. Furthermore, acting upon the strongest opinion (overriding conjecture) is permissible when certainty is absent, because absolute certainty is unattainable in most rulings.