Brookfield SN18 and Maltine bottle SN18.

Note with all of these that of course the SN would not be a perfect "photocopy" since they are hand engraved. But just like handwriting, an engraver had their own style. That s what these comparison photos are displaying.

IMO opinion, and I know I cannot prove it since we have no eye witnesses or time machines, that This style of Maltine is a Brookfield made bottle. I do believe the evidence so far (minutiae of analyzing styles in the lettering) pretty convincing the engravers making the SNs were the same people.