Hi, I just heard back from Bob (he goes by Swamperbob on CCF), here's his take on your coin:
"Sorry but it is NOT a colonial counterstamp.
I recognize the stamp in this case, it is Spanish (Mainland). The copper coins of Philip III and Philip IV were counterstamped to change the denomination. They are called "Resellados". The reference is Cayon page 570 for 4 Maravedis and 573 for 8 Maravedis. The host is from the Cuenca mint (Philip III) but since I do not have the diameter, I am guessing it is a 4 Maravedis. The date of the host is fairly common. However, many types were stamped and each mint used different punches. The trace of the stamp is not complete enough for me to tell the final denomination or mint of the c/s, but it appears to be from the reign of Philip III and not Philip IV. It dates therefore no later than 1621.
In general the stamp format is a Crowned Roman Numeral with a mint mark (one letter) centered below the numeral. The right side of the crown is clearly visible on the obverse (the Rampant Lion is on the obverse). You can see part of the circular punch outline. The upper right point of the crown is near the second P in Philippus and the stamp is only slightly tilted from the axis of the coin. The last I in the Roman Numeral (IIII or VIII) is visible directly under the edge of the crown and it extends to the S in Philippus. The side of the I and edge of the stamp obliterates the lower parts of the P and U.
The catalog value of the countermarked coppers is lower than the unmarked host (under $5). It is really too bad this one was revalued because the host alone would go much higher ($20 range).
I have appraised numerous similar coppers for local dealers and the most interesting ones carry clear multiple counterstamps. These coppers were restamped in some cases two or three successive times."
