There may have been other Colonial models, but here's one from an old Italian catalogue, and it's actually somewhat relevant, in that it is housed in a case that most collectors would (correctly) associate with Mido. It's an "FB" (Taubert) case which Mido used in high production, but UG also apparently used in much lower production.
The OP's example is actually
less uncommon, at least in terms of the case type having been used by a variety of manufacturers.
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