Watch List notes:

Charles II (1660-1685), Shilling, 1676 over 4, second laureate and draped bust right, rev. no stop after HIB, four crowned shields cruciform, five strings to harp, obliquely milled edge, 5.94g, 6h (Bull 538 [R5]; ESC -; Spink 3375), rubbed and lightly cleaned, a bolder fine, very rare.
ESC lists a 6 over 5, but not a 6 over 4. On this coin the upward serif of the 4 is clear. Bull has noted this variety, and while he lists the 6 over 5 as R (as does ESC), he lists this overdate as R5.
Estimate: £150 - £250