Possibly, but not necessarily. It might be that the exporter sucks up the lower profit margin (because, for instance, no-one else in the world is buying their stuff), or that the retailer/manufacturer does etc etc. Also, a weak pound is great news for exporters (except of course if they use a lot of imports in their exports IYSWIM).
I’m actually not really disagreeing with you here and take your point. I suppose I am really just saying that in economics (as a academic observation), it’s practically impossible to come up with any rules/laws that always work so that you can predict ahead of time what’s going to happen.