Could be, or perhaps they were set uneven on both sides? Other issue is if your tires are already quite unevenly worn, changing the camber would make the tire sit differently and affect the tread patch in contact with the road.
My mates car pulled all over the shop and loved tramlining, I set the camber to max and dropped it on coilovers which helped a bit, but he still wasn't happy with it. As soon as he put new tires on up front all was fixed!
Matt: If you're happy with it atm I'd leave it alone, I'd only recommend doing this if you swap your front suspension about, saves you worrying about the front struts being set uneven as both will be at the max. Of course if your geometry is bent in some way this will be a problem, in this case you would want to get it set by a garage.
I've had the camber set to max -ve ever since I fitted the lowering kit in June, and it handles superbly
