I already thought so since here in Germany a guy with ebay-name "sunartist60" sells decals that look exactly like yours.
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This is a screenshot of one of his current offers. When you look at the vent's decal, the "roof overhang" at digit "1" is much to long and the left and right edges of digit "6" are too straight.
Sachs-Dolmar apparently used a custom font for the digits on their decals and this font is unavailable. However its a good feature to tell good from not so good reprints.
Since the font is such a critical property I have redesigned it for my own use, at least the 10 digits and some glyphs namely "Heiprsu".
Here is a screenshot with an original decal on my 166 and my own reproduction in a layout program. It is far from being perfect, but I think its an order of magnitude closer to the original:
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