I think in reality you will find very, very few, if any for that matter, are manufactured side by side (and then cut in 1/2 for a pair, 1/4's for two pair of split, or whatever). Most I've seen are produced individually, then tested on a machine which measures something like the pounds of pressure it takes to bend the limb a specified distance. Limbs within a range of "x" deflection are grouped together, those w/in a range of "y" are grouped together, etc., etc..
Doesn't even have to be a consistent means of measurement from manufacturer to manufacturer in terms of what that specific deflection "number" is. The bow manufacturer knows via their own engineering shop which deflection is needed to produce a specific draw weight for a specific riser, cam(s), draw length, etc. for each of their bows. As long as the limbs are matched reasonable close there shouldn't be a problem tuning and shooting the bow. Most, myself included, probably can't tell if there is a subtle difference in the limb deflection for a pair anyways. Not as critical as some are making it sound, imo.
Just my observations anyhow................................
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