export vs local sales

I-O impact analysis only looks at backward linkages - what your sector purchases to produce its output (first round of indirect), what the supplying sectors purchase to produce their output, etc. (subsequent rounds of indirect), and what the employees of these sectors purchase (indirect). Thus, the impact of each of these companies will be identical per dollar of final demand, regardless of where that final demand comes from. If you can argue that local forward-linked businesses would not exist without the local company or would change their behavior (i.e., change output, employment, etc.) if they had to import the commodity, then that additional impact would be the only difference between the two, from a local perspective.