WW1 core in WW2 frame?

[Luftwaffegirl]

I know the pics are a little fuzzy but does anyone have any info about this? Thanks

[Luftwaffegirl]

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[streptile]

Seems to be a good and very rare one, but it's hard to be 100% sure from the bad photos. Maker is L59 or perhaps another one who also used this core; can't quite remember off the top of my head.

[streptile]

L/57 is the other maker it could be. Photos from pavel79 @ SDA.