Guadalajara, 1867, 4r black on blue thin laid batonne, tied by Guadalajara oval handstamp (Schatzkes 296) on 1868 folded letter sheet to Colima, Very Fine, a rare on cover usage, less than 25 covers known with any 4 reales stamp, ex Knapp; with 2003 MEPSI certificate. Scott No. 28  Estimate $400 - 600. $0 (Image)