Can someone help me date these

, one on the left Blue-point TF-528-D and the one on the right Snap-on TF-528-B.
The Snap-On I am especially interested in as it appears older and uses the metal case.
I am re-searching the Snap- On looking as well for an answer to the identity of the original tubing cutter, not much have I found but according to this site
http://www.fvstore.com/Vintage-Snap-On-Blue-Point-TF-528-B-Copper-Tube-Cutter-amp-Flaring-Tool-Set/p1141884.html the cutter is described as ..........Vintage Snap-On, Blue-Point, TF-528-B, Copper Tube Cutter & Flaring Tool SetContains TC28A Blue-Point Tubing Cutter ............
Would this Blue-Point tubing cutter be correct for this kit, as luck would have it the later kit that I show uses a tubing cutter with this very same identity stamped into the body

Id like to make this kit whole again so any help would be appreciated, Id like to find the absolute correct cutter.
Just for the heck of it I have googled Snap-On TF-528-A and received no hits, I figured there would have to be at least an A and then a B,C,D