Is this way too throw leading uppercuts?

[BCBUD]

It's hard to know where the weight should be placed inorder to throw the leading uppercut according to Fenech the weight is forward.Most Boxing Champs per nation - General Boxing Discussion - MaxBoxing.com Forums

Everything has variations.
Personally I thnk its down to the circumstance and the direction the target is moving to , like when you adjust back slightly on an angle from being squared up and catch them coming in with one ,you could end up even having your rear heel facing the point of contact as you land it on the way out. Or you could slip to his inside and throw it slightly more off the front foot or the one you just placed in between his legs.
You could also be more squared in stance nose to nose ducking weaving down there and throw it off either side depending on his direction.

@Andre yep here's a clip of the great Chavez doing that... notice how his rear leg is almost straight 70-30 percent weight distribution towards the front. A Los Golpes Con Gennady Golovkin & Marco Antonio Rubio HD 720p - YouTube