According to the Embassy of El Salvador, as stated in a telephone interview with the IRBDC, Salvadoreans who complete their military service or are discharged are not automatically issued a document stating this (7 June 1991). The source added, however, that the Ministry of Defence keeps a record indicating individuals who have completed their service or been discharged, and issues them upon request a document stating their status (Ibid.).
The Consulate of El Salvador in Washington, D.C., stated in a telephone interview with the IRBDC that people who have completed or otherwise ended their military service are given a document indicating this (certificate or constancia in Spanish). The source, however, was not sure whether the document is given without need of requesting it in all cases in which military service is ended (10 June 1991).
The Military Attaché of the Embassy of El Salvador in Washington, D.C., indicated in a telephone interview with the IRBDC that people who have completed their military service or been discharged for non-criminal reasons are entitled to and receive upon request a document showing that they have served in the military (10 June 1991). The document is not issued automatically upon completion of the service or discharge, but is issued upon the individual's request. The source added that people who are dishonourably discharged (i.e.: because of desertion or a serious crime) would likely not receive such a certificate (Ibid).
Information on how individuals are perceived by the Army after having completed their military service or being discharged could not be found among the sources currently available to the IRBDC.
Bibliography:

Embassy of El Salvador, Ottawa. 7 June 1991. Telephone Interview with Information Staff.

Consulate of El Salvador, Washington, D.C.. Telephone Interview with Representative.

Military Attaché of the Embassy of El Salvador, Washington, D.C. 10 June 1990. Telephone Interview with Representative.