I don't believe it is possible to see it otherwise, as far as I know.
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Harvey I think, therefore I am - I think! 17 May 2020 06:40:16pm
re: Is there a way to tell...
With a lot of the early tagged stamps in Canada you could easily see the tagging, one bar was Winnipeg tagging and two bars was Ottawa tagging. They showed up as dull areas on the stamps. I'm not sure about other countries.