from what i understand the 44 mm kit is OG airsal and the 45 mm kit is something they bought from another company (zeta or something like that) that went out of business, hence having two really similar kits.
i think in the mid-late 90's when all these little companies went under, athena and airsal bought their tooling and either made it in their own factories or just sent it over to taiwan/china to make them, like the AJH athena reed and the Athena reed.