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The dial looks original, to me. However, I would not call these sandwich dials as they are only made of a single disc of brass. The sandwich dials of the 1930s/1940s (by Stern Freres) are made of two discs of brass that are riveted together.
Based on the dials of @hejsam and @bubba48 , I couldn’t say for sure.
The font is different than the 35mm models (both below), more comparable to the larger one of @hejsam (top right).
But the writing is a bit of: the “G” feels strange for me.
I’m not saying the dial is a redial, I don’t have a lot of knowledge about Longines, but merely looking at small differences.
The subtle difference(s) that you note are within the acceptable tolerances. All dials shown above are quite clearly original.