i agree it is unusual . but the lugs and drop outs i reckon are typical billato .
If one were to invent a forgery and go to the trouble of pantographing the seat stay, and do such a good paint and sticker job , you would have to be a right knob or a highly skilled,joker.
what i mean is a faker such as this could make an equally as good ,fake colnago and sell for at least double.
but of course some one could have simply purchased the reynolds sticker's , an ignorant previous owner perhaps,
the internal seat post bore 27.2 both the same. perhaps s a retro bike member has an identicle one or a member in Italy could ask billato and help .