I would talk to an experienced clubfitter about the quality rating of these shafts.
The 2014 GolfWorks catalog describes the two shaft models as being versatile, and adaptable by the clubfitter. For example, in the Multi-Step Light, the L and A flexes come from the same shaft, and the R and S flexes from the same shaft. Thus, you only have to maintain two inventory SKUs rather than four. Again, this requires more skill by the clubsmith to make it worthwhile.
For shaft specs, check out the home site: http://www.truetemper.com/products/
In manufacturing, some shafts test out more uniformly for weight than flex. A veteran clubmaker told me how he would select 12 shafts as candidates for a set of irons. Then, he would frequency-match the shafts, and select the eight which came the closest to ideal flex. If the four "rejected" shaft all came out stiffer than wanted, he might put them aside for compiling a "stiffer" set of eight for some future customer. You would need to do more spotchecks on raw shafts if you weren't buying into the $40 tubes of the KBS Tour family.
Again, talk to an experienced clubsmith on this. I'm more familiar with fitting parameters than actual club assembly technique.