Their problem was that they didn’t have the means of dropping any on us. The real problem was that we had no army in any sense in Germany, and they did. It was the deterrent of Soviet belief we had piles of atomic bombs ready to go that had kept them in check. They believed we had piles of them ready to go because they would have had piles of them ready to go if they had been us.
That was not the only time the projection of their attitudes onto others came into play in their decision making.
Stalin as Sauron.
Tolkien, in his marvelous trilogy the Lord of the Rings, wrote that Sauron couldn’t imagine the West not using the Great Ring if they had it. And it never entered his mind that they might seek to destroy it. I was simply out of his reckoning.
This is an interesting list of nuclear weapons.
https://en.wikipedia.org/wiki/List_of_nuclear_weapons
https://en.wikipedia.org/wiki/Mark_4_nuclear_bomb
The Mark 4 was an emergency 1949 hand made bomb in response to Russia it would seem. Same size as Fatman. Some improvements. 550 made.
https://en.wikipedia.org/wiki/Mark_5_nuclear_bomb
Mark 5 (52-63) was smaller. Door in front to insert the fissional able material.
In November 1945, the Army Air Forces asked Los Alamos for 200 Fat Man bombs. At the time there were only two sets of plutonium cores and high explosive assemblies.
1) We never find a definite statement on how many active bombs there were or WHEN. We had exploded 3 including trinity. We can safely assume there were more in the pipe line.
But this would indicate there were two more available at the time of the scheduled invasion. And I think we would have used them in the invasion.
2) Perspective on Russia was definitely in place regarding the order for 200 more.