If the notebooks come with an oem key already - then you have already paid for a license for each machine.
No sense in paying again.
You should be able to create an image using sysprep including the drivers
and install it to all the notebooks.
Probably easiest to do a clean install of Starter edition from regular install dvd - install drivers and any other setup stuff - no need to put a key in at this stage - sysprep it - then put that image on all the machines.
You would need to put each product key in individually - shouldn't be a big deal if you only have a couple of dozen .
I don't do this for a living - just working on logic.