§ 327.26
State and local laws.
(a) Except as otherwise provided in this part or by Federal law or regulation, state and local laws and ordinances shall apply on project lands and waters. This includes, but is not limited to, state and local laws and ordinances governing:
(1) Operation and use of motor vehicles, vessels, and aircraft;
(2) Hunting, fishing and trapping;
(3) Use or possession of firearms or other weapons;
(4) Civil disobedience and criminal acts;
(5) Littering, sanitation and pollution; and
(6) Alcohol or other controlled substances.
(b) These state and local laws and ordinances are enforced by those state and local enforcement agencies established and authorized for that purpose.
[65 FR 6903, Feb. 11, 2000]
Since item (a) says Except as otherwise provided in this part or by Federal law and this is included in the in Federal law,
§ 327.13
Explosives, firearms, other weapons and fireworks.
(a) The possession of loaded firearms, ammunition, loaded projectile firing devices, bows and arrows, crossbows, or other weapons is prohibited unless:
(1) In the possession of a Federal, state or local law enforcement officer;
(2) Being used for hunting or fishing as permitted under § 327.8, with devices being unloaded when transported to, from or between hunting and fishing sites;
(3) Being used at authorized shooting ranges; or
(4) Written permission has been received from the District Commander.
(b) Possession of explosives or explosive devices of any kind, including fireworks or other pyrotechnics, is prohibited unless written permission has been received from the District Commander.
[65 FR 6901, Feb. 11, 2000]
it seems that state laws on this issue don't matter.
State hunting laws would apply when hunting on CoE land, but I still don't believe it would be legal to carry a firearm on CoE property.