No,definitely not. .458 Win magazines are of the so-called "M-Sch Magnum" length, as long as Steyr could make them. There is no practical way to lengthen it. They will take cartridges up to 85 mm = 3.35" over all, not a hair more. The Winchester has a max. oal of 84.8 mm = 3.34", so it barely fits. The .458 Lott has a max oal of 91.44 mm = 3.6", to long for the M-Sch magazine. Of course, in handloading you may seat the bullets in the Lott to a shorter oal. Doing so, you will loose any powder space advantage it has, compared to the Winchester.
See these threads too:
http://forums.nitroexpress.com/showflat.php?Cat=0&Number=122479&an=0&page=2#Post122479
http://forums.nitroexpress.com/showflat....true#Post237830