Donor Nand:
The nand information is useless on the other board unless the dash version/CB match. If they do then you can use it as a donor nand and replace the KV with the box you are trying to fix. There are plenty of post on this forum on donor nands, do a search.
Chip removal tips:
Are you using flux paste? That works wonders. Put some on the solder pads and it will start bubbling to let you know the temp is close. It also warms up the pads under the legs where hot air can't hitting directly (Can buy at Radioshack). The electrical tape will also get really sticky when heated. You are better off using metallic tape that is used for air vents (Sold at hardware stores) or no tape at all. For that gun, keep it about 3-4inches above the chip and oscillate constantly. 200degree for about 3mins (Pre-heat), 500degree for 2mins and then 800 for about 10-20sec. A suction pickup tool is best, but if you are using pliers, don't just pry it up, first push on it slightly, if it moves, you are good, if it doesn't, then continue to heat before picking it up. If your work area is really cold, you may want to start by warming up the underside of the board at the 200degree setting. Leaving the underside cold requires a longer pre-heat and can cause warping. I place my boards on a 2 inch high stand, place it on a griddle, and heat at the max setting for 4mins.
Causing damage:
800degrees can cause damage if left on too long. Using 2mins at 800degree after 200/500 settings will start damaging components and the board can start separating. If you are worried about 800degrees, 500 setting will eventually melt the solder if the gun is close enough and you are using flux paste. If the solder is not melted, then don't worry about damaging the chip. I would be more concerned with the caps that are close to the nand. Protect them from direct air, but don't completely cover them or the foil will act like an oven!