I can't really speak to the politics of it, but a few thoughts on the technical aspects.
"SILVERPLATE" atomic-capable B-29s and non-fissile A-bomb components were sent to Guam IOTL in early August 1950, around the time of the battles you mentioned. However, I don't believe the weapons would ever be transferred to Korea even if they were intended for use there. B-29s used in support of operations in Korea were based out of Okinawa. Also, IOTL the weapons were no longer under control of the AEC once they left the CONUS; they were under USAF control, and likely would be ITTL as well.
Edit to Add: I mean they were held by the USAF, in their custody, not that the USAF could decide to use them without Truman's say-so. I think I may have been a bit unclear earlier: the AEC was not going to transfer weapons to the military without Truman's instructions. But, once the weapons were sent to Guam, they were pretty much out of the AEC's hands.
I wonder if, rather than physically seize the weapons, MacArthur might instead suborn the base communications, replace the radio operators with personnel loyal to him and issue a phony order to attack. I don't know how the Air Force's communications were set up in 1950, so I don't know if that's plausible.
"SILVERPLATE" atomic-capable B-29s and non-fissile A-bomb components were sent to Guam IOTL in early August 1950, around the time of the battles you mentioned. However, I don't believe the weapons would ever be transferred to Korea even if they were intended for use there. B-29s used in support of operations in Korea were based out of Okinawa. Also, IOTL the weapons were no longer under control of the AEC once they left the CONUS; they were under USAF control, and likely would be ITTL as well.
Edit to Add: I mean they were held by the USAF, in their custody, not that the USAF could decide to use them without Truman's say-so. I think I may have been a bit unclear earlier: the AEC was not going to transfer weapons to the military without Truman's instructions. But, once the weapons were sent to Guam, they were pretty much out of the AEC's hands.
I wonder if, rather than physically seize the weapons, MacArthur might instead suborn the base communications, replace the radio operators with personnel loyal to him and issue a phony order to attack. I don't know how the Air Force's communications were set up in 1950, so I don't know if that's plausible.