I believe it is a Juncker, but it's not exactly proven, to the best of my knowledge.
Here's mine -- I call it the "flawed frame" because long flaw runs down the 7 o'clock arm beading strand. The core in this one is one that Carl (Roglebk) has called the "small RK" core, I think because the date numerals resemble the Juncker RK dates.
Confusingly, this frame has also been found with cores that Juncker never used (to my knowledge). For example:
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