Bolivia 1867 First Issue

 The stamps were engraved by Estruch La Paz and printed at Cochabamba. 

There are many types of these stamps as can be seen by the 5c block below. 

They were generally used for fiscal purposes, about 75%  (cancelled by pen strokes).

Due to poor ink quality, there are many color shades of these stamps.

Genuine Stamps

The variety of types in the same sheet are clearly visible.
This makes determining if genuine very difficult.

Forgeries

5C

I am not 100% sure this is a forgery

10C

50C

100C

Bottom numerals are inverted

Broken O in CORREOS

These are probably all from the same forger

The 100c bottom left numeral reads I100C

Taylor-Spiro Forgeries

Bogus Issue

According to a published report..

"F.C.Milne of the United States consulate at Cobija Bolivia has heard from Don Alberto de Barios of the Bolivian postal department (actually Samuel Taylor) that the following set of stamps were issued (with dates of issue):

5 centavos green and 5 centavos pink [qy.lilac] March 5th, 1867

10 c brown April 1st 1867

15 c blue (dark), 15 c green, April 20th 1867

20 c red May 1st 1867

50 c blue, 50 yellow, May 10th 1867

100 c blue, May 10th 1867

1 peso deep red, 1 peso blue, June 1st 1867

This looks like a scam to get the bogus values 15 c blue, 15 c green 20 c red, 1 Peso grey and 'UN PESO' blue in the market.

Sperati Forgery

Type A & B

Type  A

1. top serif of the numeral "1" in top left oval is broken at right

2. there are spots between the design and the upper frame line and above the frame line, also between the two final letters of "BOLIVIA" and below the "A"

3. there is an extension of the horizontal line of shading over the "T" of "CONTRATOS"

Type B

1.  there is a fine colored line extending from left frameline into margin opposite the "OS" of "CORREOS"

2. there are two spots below and two above the top frame line over the "OL" of "BOLIVIA."

3. there is a spot between the numerals in the lower right corner and another above the "O"

4. the top right numerals have white voids

Torres Forgery -  from his 1892 Catalog