The stylized EL was applied at the time of the first Provisional Proof. It's pretty common to see it double stamped, and I don't know why. Maybe at the 2nd proof of the joined tubes.

Nothing definitive on the 'ACCI' and I haven't found a barrel maker with those letters (which the Belgians tended to dyslexicly rearrange for our confusion wink ). Later SPI doubles frequently had the ‘LLH’ of Laurent Lochet-Habran and 'ACL' in an oval of Acier Cockerill Liege
Maybe Société Anonyme John Cockerill??

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