Introduction
The main production centers for Punjabi metalwork and koftgari overlay were Sialkot and Lahore. In identifying the gold work, that of Sialkot tends to consist of narrower lines of gold where Lahore work is often much denser, utilizing thicker lines or sometimes having the design appear in the negative space. Many shields were produced, of which this is an exceptionally well-preserved example.
 
This example
A very fine steel koftgari shield from Sialkot. The face is decorated with gold wire overlay in geometric patterns and creeping vine motifs that may resemble very stylized branches of one of the sacred trees revered by Sikhs and Hindus. The steel background was blackened to make the designs stand out more.

Around the shield are four cartouches with Persian calligraphy, executed in a skillful hand:

با بدان منشین که صحبت بد / گرچه پاکی تو را پلید کند
"Do not sit with the wicked, for bad company / even if you are pure, will make you impure"

This is a well-known moralistic couplet about the corrupting influence of bad companions by 12th-century Sufi poet Hakim Sanai. It was published in the Hadiqat al-Haqiqa (Enclosed Garden of the Truth) around 1130–1131 AD. It is a poetic masterwork that inspired famous later Sufis like Attar of Nishapur and Rūmī and his companions.

The inclusion of a Sufi text on a Punjabi shield is no coincidence; the Sikhs of the Punjab had a strong connection to Sufism. The primary Sikh scripture the Guru Granth Sahib of 1604 included the poetry of the Punjabi Sufi saint Baba Farid (Sheikh Farid) alongside the words of the Sikh Gurus.
The reverse of the shield is covered with padding made of wool and red cotton fabric glued on the back. In contrast to the well-preserved front, the textile has many losses. See photos.

Provenance
The shield came from the Richard R. Wagner Jr. Collection. It was published in Oliver S. Pinchot; Arms of the Paladins, the Richard R. Wagner Jr. Collection of Fine Eastern Weapons. Woonsocket, USA. Andrew Mowbray Incorporated. 2014. Page 161. 
It was described there as "a typical Mughal shield with Persian influence, mid-19th century, probably Udaipur" but that is clearly incorrect. The designs and method of application are very typical for Sialkot. It may be that Wagner or Pinchot have seen a similar shield in an Udaipur collection, which got there by tribute or trade.