Lot
90 
Fair Play Colo. Mar. 23, duplex postmark on registered 3¢ green Postal entire uprated with 1870 Grilled Bank Notes 2¢ + 7¢ addressed to New York. adhesives cancelled by cork cancel, manuscript notation "Reg no 86", 7¢ with couple blunt perfs, Very Fine and scarce. Estimate $200 - 300.
While the usage is somewhat late for the grilled stamps, this cover dates to either 1874 or 1875 (and is thus territorial). The registry fee was 15¢ until January 1, 1874, when it dropped to 8¢. It went back up to 10¢ on July 1, 1875, so this cover would have been underpaid either before 1874 or after mid-1875. Instead, this is a one cent overpayment. It seems reasonable that a remote territorial town would have had little use for 2¢ and 7¢ stamps, and these were likely still in stock from an 1871 shipment.
Realized: $200