Your D2 was manufactured in 1938 and was purchased from Goughs by W. Gregory of Waiau. For the tank, I'd say just get a new one. For the mag, if it's not hot, then send it away to be restored. They come back like brand new. For the carb, you'll need the kit but also there is some technique to cleaning them out properly. When you remove the bowl from the throttle body, be careful because there's a thin brass tube that screws in from the other side and goes all the way across the throttle body into the bowl assembly. If you can gently unscrew it first, that's best but sometimes they get seized in there and it's often best to leave them alone as I don't know if you can get them new. You may need to drill out the lead plugs on the bottom of the bowl to clean the passage that runs across the bottom to the well. They're easily to replug with 177 calibre air rifle slugs and if you want, a bit of glue over top of the slug. The "bull's eye" gasket between the throttle body and bowl has a center ring that sometimes fails so make a note if that was the case when you disassemble it. Finally, there's a plug situated just under the throttle plate when it's closed that acts as the "jet" for the idle circuit. Check that the notch in that plug is under the plate (on the engine side when the plate is closed) so that the idle circuit can feed gasoline to the engine at idle. Mine had been reversed and would not idle despite a full clean and refurb. Very easy fix. You just find a close fitting punch, punch it all the way in, then fit it again from the outside the right way up. Make sure the throttle plate is out of the way if you do this.