How extensively has Bluebird been rebuilt during its life? The stern area of Jason's model looks quite different (and Bluebird appears to be shorter). My guess would be a "freelance" model in the same style as Bluebird, or a model of a real boat designed in the same way (as others have suggested) but I'm definitely not an expert.
It's an amazing find, anyway

It's a shame what people throw away sometimes having no idea of its value or historical interest. The only item of model boating interest I've ever found in a skip is an old wooden galleon model from the 1930s - but only a few weeks ago I found a part-built (hull + deck with radio + motor installed, plus some loose fittings) 1/64 scale V&W class destroyer at a car boot sale for £10! The seller even threw in an old pond yacht hull for free (see my other post). I'll post some photos of this when I've got the running gear sorted out. It needed a new ESC and battery pack, and the motor is going to need re-aligning with the prop shaft, but the RX, servos, motor (MFA), rudder and brass propeller were all salvageable, despite (judging by the amount of cobwebs, rust and junk inside the hull) having been in an attic or garden shed for the last 20+ years.