Two identical cameras in Lightroom

My wife and I both download all of our images into LR, and have done for some years. We can always tell who took what by the info on camera, lens etc. However, I'm thinking of replacing our current (same brand but different model) DSLRs with identical Panny G5s. Two problems strike me about how LR is going to react:-

1  We won't be able to figure out who took what, except perhaps by checking on lens used for an image.

2  Both cameras will presumably use identical numbering regimes - so we are likely to have duplicated numbers for different images. (Maybe I should cross-post this in the M43 forum so that someone who knows if a G5 can be tweaked to alter the numbering can answer.)

Can any LR expert throw any light on how to get round this issue? Many thanks.

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Paul Graber