Maybe or maybe not, we will never know that. Who knows how things play out when a country is integrated back in the international system and have something to lose when if get caught on checks. Maybe there would have been a book about how Iran continued its clandestine nuke program but eventually dismantled it as its society and economy normalized and having that had no benefits.
Now we know the timeline where agreements are not honored by the US.
Look, I don't know why you believe so much in the imaginary timeline but maybe Iran would have been like Israel: having the bomb and not talking about it.
Who knows, it's all speculation at this point. The current reality is that if you don't have a nuke you get invaded. Everyone will have nuke soon. Those who fail will be destroyed because agreements, international laws etc doesn't mean anything anymore.
Now we know the timeline where agreements are not honored by the US.