Most of the signed prewar cards that currently exist in the hobby were signed well after the player featured on the card retired. However, consider the following article, which was posted on Net54 some years ago:
In addition, below is a link to a very brief article about a group of 1871-72 Warren CDVs, which were all signed during the players' playing days -- six of the players added date notations to their signatures, each within a span of three days from July 22nd 1872 to July 24th, 1872:
https://www.signedt206.com/earliest-...baseball-cards
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