Well we know they did have arguments from time to time like any couple given how Kushina mentioned that their deaths was also when Minato won an argument the first time between them.
Has she ever hit him? I woundn't be surprised given Minato has his own nature of being too "quick" guess we can say after he gave the rasengan + amterasu attack a long convoluted name.
I mean yes Naruto has aspects of both his parents for his personality, just not common sense like Minato but still a brilliant fighter. Did Kushina ever hit him though? Well it wouldn't be surprising if during their younger years someone may have ticked Kushina off and Minato got caught in the crossfire kinda like when Naruto tried to do damage control when Sai insulted Sakura but she just whacked them both. RtN kinda gave a small example of how Minato and Kushina lived I mean she still had her temper but Minato managed to work with it trying to get her down to cooler levels. I could see that relationship being something from time to time should Naruto and Sakura end together. But its just that again, Sakura hitting Naruto is one part he kinda deserved it from time to time to keep him in line, the other part its just common comedy. People who try to demonize Sakura for this and no other common anime characters who do this are just not making any sense with a notion like this. Sakura hits Naruto yes, but its just a minor comedic element between them. Its so funny how those people who hate her constantly forget her main talent, shes a medic so she can heal him as much as she beats him, rather Naruto can withstand her attacks, its just generic manga comedy when someone is beaten to the scale they should have died but its done in an outrageous scale at times just to add humor. Its that simple. Besides, when did Sakura last hit Naruto? When did she last strike him in any form that was considered a pummeling like the reunion in the start of part 2? I remember that being around when Sai was introduced. Not going by the manga, thats a very very long time. Yes she hit him before the hug and headbutted him during the reunion with Minato, but those were not serious, one hit was for Naruto being reckless, the other for not focusing on the current fight and calling Sakura his girlfriend (well we know Naruto still has Sakura in his eyes).