Have them polish the barrel, but just leave it in the white. If you plan to have someone else blue it, the scouts aren't learning that part anyway. Spend a bit more time on the wood and "fitting" the barrel, tang, lock, and ornaments (hey, if they can put so much muscle into those wooden derby cars the gun furniture should be a piece of cake). This way they learn some more attention to detail. You could do the blueing as well with a cold blue from any sporting good store. Just my $.02
Traditions are fine for what you plan to do.
This message and signature were both made using 100% recycled electrons.