It will fit, as the frames are the same aside from a couple extra bolt holes in the gen2 for the fairings. The external engine dimensions are almost the same also.
The throttle bodies, airboxes, ram air tubes and lots of small parts are all different too.
It won't just be a bolt in and ride job.
A gen2 can be had for in the $7k range, and some great deals of around and even under $6k are out there occasionally.
You need to decide what parts you'll need to buy, and if you can do the work yourself.
The gen2 has 41 more cc's, more power, and a better transmission.
If you're a good fabricator and have a gen1 for doner parts it's doable, but a gen2 engine from a crashed bike can be bought for around $1500 to $2k average.
Then you run into title and mileage issues of what appears to be a newer bike. All of which affect resale.
Personally I think it would be a money pit.
Whatever info you need, someone here has the answer. Welcome to the org.