2 pesos late paper "Servicio Oficial" selection: the overprint

 Independent of finding three different stamps: a neat blue center Zarate, a diffused blue center Zarate, and a dark blue 1L6 with at least one example from the family of wobbled kiss prints and even double prints of the center, the "SERVICIO OFICIAL" overprint is the same for all three major variants. Here is a sample:

Some neat printings:

Some diffused printings:

The 2P1L6 printing:

From the doubled center specimen:

2 pesos late paper "Servicio Oficial" selection: two papers

I see two papers during the late papers period of 1951-1957. 

1. There is a 2P1L with somewhat clear to diffuded RA watermark which I have referred to as 2P1L5-Zarate before:

And then there are instances where the paper has a barely visible watermark. I do not know if this is the same paper of varying thickness, or there were two separate printings each on a different paper, but they all look very similar, and so I am calling them all 2P1L5 for now.

Since the colors of all of the 2PL-SOs I have is the same, I am leaning to this stamp just being one printing on Zarate paper that sometimes shows the watermark clearly and sometimes shows it only barely (latter is the signature of Zarate papers).

There are two Zarate prints: one with diffused blue center, and another with very clear blue center, characteristic of plate cleaning.

Diffused:

Neat and clean plate:

2. The second paper is 2P1L6, and this paper is a lot easier to type because it is white and porous with a clear RA. Also, the center is a darker blue consistent with the regular issue equivalent of this stamp:

The 2p1L6 has various wobble, shadow and full double prints of the center typical of the base, regular issue. The specimen below can only de described as a doubled center with very little displacement between the two prints.

Two 1943 15cMG slogan ship covers

 The first cover has the slogan "the 20 percent reduction in leasing costs is an agricultural achievement."

The second cover has the slogan "The national telegraph accepts out-of-country telegrams."

Two Slogan Ship Covers from 1943

 The first envelope is a 3c circular rate with the "Visit Argentine" slogan.

The second cover is a 25c regular rate with old-style slogan "Don't incude money in your correcpondence; Use the service of postal money orders or the declared value service.

A Continental Grain cover with 50c stamps

 This is an airmail 1.15 pesos rate postmarked March 1943 with slogan "Sent money out-of-country using the post office."

1943 Censored Cover to Brazil

With tape applied in Brazil and slogan reading "The national telegraph accepts out-of-country telegrams."