I wouldn't worry too much about differentiating between the various models. I'm not military, but to me an F18 is an F18. Do you need different training events and proficiency flights to qualify in each different model?

At the end of the day, I don't think most people are going to care too much, but I'd say that it's really up to you how you log the aircraft. What they do want to see is that your flight times are accurate and honest.