Unique Vintage WMP Slingerland Snare Drum 6 1/2x 15!

This is one special, unique, collectable drum!
I have tried identifying it using the Rob Cook Slingerland book. It does not fit neatly into any of the pictured snare drums, but I am guessing it is a Concert King model.
First of all, it is a 3-ply shell (maple-poplar-mahogany), not a single ply (so if you identify "true" Radio Kings by the single ply shell it is "not" a Radio King.) But it does have the Radio King style "Clamshell" strainer, which is in great working condition and very good cosmetic condition (one side has some pitting shown in the picture). The small oval brass badge (no serial number "Chicago") indicates that it from the mid 1950s, and it has NOB Sound King lugs and NOB hoops. (I replaced the original top NOB hoop with one of a similar vintage because the original was bent.) Finally, it is a 6 1/2 x 15 (that's right 15, not 14), like a "Concert King". I have Puresound blaster snares currently on the drum.
I have gigged this drum and it has a deep fat sound, like a Radio King, but because of its size even fuller. Put it on shelf or play it as your "go to" snare, don't miss out on the opportunity to own this one-of-a kind Slingerland drum!