1904, 8c on 50c Bister Brown
(15). Original gum, rich colors, left "Panama" split
horizontally and approaching the Two Panamas Close Together variety,
choice centeringEXTREMELY FINE ORIGINAL-GUM EXAMPLE OF THE 1904 8-CENT ON 50-CENT BISTER BROWN CANAL ZONE ISSUE. ESPECIALLY DESIRABLE WITH THE SPLIT OVERPRINT.
With 1976 P.F. certificate not noting the variety. (Image)
1920, 2c Orange Vermilion &
Black (47). Original gum, lightly hinged, bright colorsVERY FINE AND CHOICE EXAMPLE OF THE 1902 2-CENTESIMOS MOUNT HOPE OVERPRINT.
The rarity of this stamp in unused condition is reflected by the difference in Scott Catalogue values of $3,250.00 unused versus $100.00 used.
With 1974 A.P.S. certificate (Image)
GUAM, 1899, 10c Brown, Ty. II
(9). Original gum, pretty pastel color on bright paper, wide
marginsVERY FINE AND CHOICE ORIGINAL-GUM EXAMPLE OF THE RARE 10-CENT TYPE II WITH GUAM OVERPRINT.
With 1979 P.F. certificate (Image)
GUAM, 1899, 1c-6c, $1.00
Overprints (1-6, 12). Tied by purple "Agana, Guam" straightline
handstamps on registered cover to Germany, Jan. 26, 1901 transit and
receiving backstamps, typed "Registered! One stamp each at 1, 2, 3, 4, 5,
6c & 1 Dollar" at top, some slight toning around perf edges from gum, faint
horizontal file fold at top clear of stamps, Very Fine, scarce and colorful
usage (Image) 
GUAM, 1899, 2c-$1.00
Overprints (2, 5, 8, 11, 12). Tied by blue "Guam Ladrone Isls. Aug. 24,
1901" duplex cancels on registered cover to Germany, blue "Agana
Guam" dateless handstamp with ms. registry no., transit and receiving
backstamps, some toning around stamp edges from gum, light vertical file
fold at far left well clear of stamps, Very Fine, scarce and colorful
high-value franking (Image)