The lens is sort of recessed - not flush with the body as I recall. I suppose it won't be much of a problem except perhaps for dust? A lens cover is a better idea, but I wouldn't buy a phone based only on that.
Of course you realize taking pictures will look better viewing on the LG 6100 because of its bigger and brighter screen. I imagine the flash on LG 6100 will provide better indoor shots and help out where more light is needed. If taking pictures is a high priority of yours, you might want to give more consideration to the LG 6100.