Conversion of a value between g/gmol and lb/lbmol

I am doing some air emissions calculations and I really just have a bad feeling about my results. By definition, molecular weights are given in $\pu{g/gmol}$. For the substance I have, I was told by a technical contact at Citgo that this material has a molecular weight of $\pu{140 g/mol}$ (which should be $\pu{g/gmol}$). Whenever I convert this $\pu{lb/lbmol}$ (which is required for this particular equation), I'm getting a value of $\pu{0.3086 lb/lbmol}$. There are 453 grams in a pound. Is it not correct to divide 140 grams by 453 grams to get the total number of pounds?

My final result for annual emissions is pretty low.

A gram-mole ($\pu{gmol}$),often just called a mole ($\pu{mol}$), is the amount of a material whose mass in grams equal to the numerical value of the atomic or formula mass. For example, a gram-mole of water has a mass of 18.017 grams, this number being the formula mass for water.
A pound-mole ($\pu{lbmol}$) is the amount of a substance whose mass in pounds-mass equals the atomic or formula mass. For water, one pound mole has a mass of $18.017$ lb-mass.