rod mix-up? question

First, you couldn't feel by lifting if they truly "weighed the same". Identical factory rods don't. Factory weight matching consisted of grabbing 8 rods and stamping them 1-8. Performance balancing requires the individual ends of the rod be IDENTICAL. We're talking fractions of grams here, not something you can notice, not something most typical (even postal) scales can notice. Plus you ned to weigh each end individually.
Or, just slam it together and hope it's good enough to work.