Help Needed With S.american Stamps (Arg.-Ven.)

Got a large stockbook with South American earlier stamps, presorted approximatevily by country and era (from Argentina to Venezuela). I guess there are among them reprints (forgeries?). I intend to sell them (not my area), but with little knowledge that would be impossible. Let`s start with Argentina, larger better scans will come soon. Help please!

For the 5 c, the genuine stamps have 72 pearls in the circle, forgeries with 88 pearls exist. The 10 c has 78 pearls and the 15 c 71 pearls.

Also Stanley Gibbons of London (the same one from the catalogue!) acquired the plate of the 5 c value and made private reprints of it. According to 'The Forged Stamps of all Countries' by J.Dorn they can be recognized by the absence of shading in the cap and a worn appearance.

These reprints thus also have 72 pearls, but they are on heavier paper and in the wrong shades of red. Gibbons also changed the value indication '5', to '10' and '15', however, in the genuine 10 c and 15 c stamps, the 'C' of 'CENTAVOS' is broad, while in these 'reprints' the 'C' is the same as in the 5 c value. These reprints were made in 1870.

Could be Spud papers material
Hope that gets you started

Thanks, greatly explained, and solved the 10 and 15 cents (narrow C as in the 5c value)- so reprints or forgery.

A good book on Philatelic forgeries.

http://www.amazon.com/The-Spud-Pape...p/B002LMDGHO

Venezuela (1/2 c and 2 reales 1865-70 ??), the CV of Y&T suggests that these are reprints or forgeries too,