Dave,
As I said above, I don't own a Stanley 140, so I can't give you comparative weights between the Stanley and the LN bronze 140. This morning I weighed my LN bronze 140, a LN adjustable mouth block plane (60 1/2) and a Stanley 60 1/2. Here are the weights for each of those:
LN bronze 140: 2 lbs even, without the fence assembly; 2 lbs. 3 1/2 oz. with the fence assembly.
LN adjustable mouth block plane (60 1/2): 1 lb 11 oz.
Stanley 60 1/2: 1 lb 5 oz.
Just for fun, I weighed my LN Bronze 102: 15 7/8 oz.
Hope that gives you something to go on.
Hank