1870-S 50c Seated Liberty Very Small 'S' Variety Verification

Yes it is WB-1. All of the 1870 S mintmarks are rated as very small and are the same size on all four reverse dies. Key identification feature is the position of the mintmark. On WB-1 it is positioned to the left below the arrow fletching. on the other three rev dies the mintmark is just a little left of being below the "notch" formed by the fletching and the olive branch. (WB-1 is the same as the WB-101.)

The WB-1 is not that rare a variety and is rated As somewhere between R-3 and R-4, "Not so common" and Scarce. 76 to 600 estimated to exist.