I'm no expert on stamps from this country, but they are Argentina Provincial Government Stamps of 1858. I'm not sure if they are authentic, though. I have a very old Scott WW Catalog that lists them at the very end of the Argentina listings under the sub-section "Buenos Aires", as the "A1" design and #1 through #8, however, the Scott catalog goes on to issue a warning that:
Quote:
"Counterfeits of Nos. 1 - 8 are plentiful."