No, it's just all the wrong colours.
Silver reacts with clear glass to produce yellows and ochres - the intensity of colour will depend on the concntration of silver present.
Silver nitrate is used to turn red glass brown, but it is still the silver that does the colour thing.
If any silver molecules escape acidentally during the making, they will often deposit on the surface of the piece in what is called "iridesence" (when it comes to Mdina anyway), but it is actually more of a mirror - but blues and yellows may appear because of reactions with glass - it's all stuff that happens in the heat!
It is also silver metal which can produce a sort of electric blue haze in a thick casing.
It doesn't look like normal enamels at all.