Vintage Black Tea Kettle Teapot w/ Bird Steam Whistle Kamenstein ?

Description

As best as I could tell from research, this might be a Kamenstein tea kettle because the bird whistle matches ones I have seen. However, I could not find the tea kettle.
Kettle measures 7" in diameter (not including spout) and approximately 8" to top of the handle.
Bird whistle is has no chips or cracks, but is stained. I did not want to try bleach as I do not know the material - feels like an early plastic.
The kettle is in excellent condition other than the bottom that has some chipped enamel.
The rubber (?) band on the spout appears stained.