The above method is lucidly, rightly outlined.
(However, on a somewhat related note, some sort of gender swap glitch is infecting Fable 3 co-op lately, even purely offline internal play between sub-identities on the same console. Hopefully, an update adjusts as necessary: not updating on the developer end is plain stupid - not only commercially - the fan-base of Fable 3 is still significant, even on Xbox One. Allowing this game-breaking glitch to persist shall darken the anticipation for Fabel IV, to only mention the least of motives for the developers or game-engineers to fix this glitch.)
Be aware, however, the RANDOM element is hardcore here - if one is an aesthete in this area, it may take literally, several HOURS or more to achieve one's desired outcome.
There is no method but madness only in the Fable 3 Hero-Weapon morph system, practically speaking...
Slaughter thousands, tens of thousands even, of the nastiest "Sire Balverines" (white balverine pack-leaders), Blooded-Balverines, all variety of deadly lupine beasts, etc.? Looking for that awesome black coloration associated with such lupine carnage? FORGET IT! - that one single chicken you accidentally kicked ONCE, shall predominate in the morphological "roll"... Kicking a chicken gives you a lackluster golden color, I KID YOU NOT. IT SHALL HAUNT YOU.
Aesthetes and perfectionists, be prepared for GRUELING PAIN here...
BTW, for interested parties, ENDOC's Weapon-Graph/Chart analytic thing on here, provides the EXACT description of each in-game Legendary Weapon in terms of the Hero-Weapon morph system, very helpfully... (The only inapplicable ones of course, are the DLC items - the Black Dragon, etc. - characterized by unique, inimitable morphological distinctiveness, almost as their "selling point"...)
For real, does anyone appreciate ENDOC's multifarious, hugely informative efforts around here, seriously? No one else has even attempted to analytically grasp the Fable 3 "morph" aspect for weapons, or the scientific "relative randomness" of weapon-drops, etc., etc. like ENDOC has - he is alone. I hope he is given acclaim one day.