Just wondering why the change in name? There isn't a single watch on the planet made of metal (I should know; I work in a jeweller's!) so why change it from 'steel'? Very odd.
Well, steel is a metal (or metal alloy to be more precise) isn't it? I believe there are watches made in other metals and alloys including aluminium, titanium, gold and silver and so on. So yes, to cover watches in other metal materials than steel, the name change make sense.
Just seems a bit pointless really. I mean, we don't get many customers coming into our shop and asking for a Rolex model 'in metal'. We do, however, get several each day, asking for a model in 'stainless steel'. There's an old phrase, if it ain't broken, don't fix it. Obviously, you don't think it applies, in this case. Very strange.