Does not look like the Brampton headset to me. The top bearing cover, while knurled, doesn't look like the Brampton bearing cover at all. Unfortunately there were hundreds of similar steel headsets like these manufactured over the decades. It looks like it has a dog's breakfast of various washers added to achieve the right stack height.

Headsets like these with the teeth ("microadjust") need a matching toothed washer to interlock to stay in adjustment. If there is no downward-facing toothed washer, the top bearing cover is likely to rotate, messing up the bearing preload. See this Stronglight for example:



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