Thanks everyone for the input an advice. On closer inspection the Slim i was originally looking at appears to have some of the plating missing on the head. As this could render it unusable, to be safe, i though i'd give it a pass to be safe. I quite like the Gillette Slim Adjustable Aristocrat in gold as I don't have a gold razor yet. Are they worth looking at?@Dru Welcome, and make sure you have fun with going down the rabbit hole lol.
As KeenDogg mentioned about the knob, here is a picture showing the differences that I pulled off the net a while back and I added the note about the knurling on the knobs:
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