I am a flutist and I don't know anything about oboe. Since I wanted to learn to play oboe I bought a used buffet oboe from ebay and the seller told me it is a 4151 student model. but since it didn't look like the photos of this model (it doesn't have Low bb resonance key) I wrote to buffet indicating the serial number and they told me it is an Prestige Green LinE BC3613Ga oboe but, it is impossible because it is an student oboe. Now I'm really confused so, can anyone help me to understand where the problem is and what is the model of this oboe? I post some photos of it.