I had one given to me about a year + 1/2 ago, very similar situation. There must have been tons of those things sold! You'll have a tougher time flying it with the mechanical gyro. Be VERY skeptical of the radio batteries - they've probably shorted out by now.
I just recently sold the mechanics; kept the engine. The big hassle with Kyosho is parts availability. You'll have a hard time finding them; 'Ricks' still has a pretty good stock. Kyosho seems to be having problems with part distribution, especially lately. Tower Hobbies used to carry Kyosho heli parts, but has discontinued almost all. I see in their new adds they're listing Century stuff instead. I wonder what Kyosho plans to do for parts availability in the US?
I just recently sold the mechanics (to 'littlepiston', no less!); kept the engine. The reason I sold my Concept was just that - the hassle of getting the parts. I spent some bucks to get a Raptor instead. It doesn't fly the same - seems 'twitchy' in comparison (but I'm getting used to it), and it seems awfully heavy to fly with a plane-jane .32, but it does fly. The big plus is parts ARE available - I have (2) local sources, and a bunch of internet sources. And, you WILL need parts - due to crashes at first, but as things wear out.
You could fly the concept - pretty much as is - until something wears out, or you crash it; and then start over with another machine - ? Depending on what the radio is, you may be able to use the radio & engine on a different machine. So, you probably don't have much to lose (assuming you got it cheap / free!)
On the other hand, if you're ambitious, you could retrofit parts from other machines as needed. Century Hawk parts should be pretty close for some of the pieces.