Yep, if it's a F-104G or J, then it'll be OK for a CF-104. There were some differences, such as the instrument panel lay-out, main gear doors and wheels, and a few other small details, but the basics were the same. The Vulcan gun was removed in the early days, and the gun port fared-over, but was re-fitted when the CAF's role in NATO changed in the early 1970's. The C-2 ejection seat was also retained.
Externally, the immediately visible difference is the tail fin and rudder, which was wider, and slightly higher, on the 'G' and CF-104, compared to the 'C' model, and you'll be able to see this when I do the conversion on the old ESCI F-104C kit. Meanwhile, here's the scale drawing compared to the 'C' fin again, which clearly shows the difference.
The Hasegawa kit is definitely the best overall, but the old ESCI or Italeri kits aren't too bad - better fit than two Revell/Monogram versions - but need to have the heavy, raised detail removed, and are basic in detail, with a fixed, one-piece canopy.
Let me know if you need details pics and drawings, as, in addition to the stuff Geo kindly sent me, I've collected quite a bit of info on the Canadian Starfighters.
Nothing more to show at the moment, as I've been either too stiff, or busy with other things today. I'm hoping to make some good progress over the weekend though, so I'll post another up-date when I get something to show.