The anchor point for the brakes for the girder forks is different to the ones for the tele roadholders,
so it depends on how that bit has been done, need to see a detail pic of that.
BTW, these type brakes were optional extras for many models both prewar and postwar.
Durned expensive though, so very few were sold as options (?).
That slim alloy rim makes it look like it could well be a full postwar wheel and brake.
Is it a Dunlop rim ?