There probably was some inflation, and here's why.
Probably you saw some repeated questions, and even if you didn't recall the answers to the repeated questions, the familiarity of the repeated questions probably caused inflation of your score in the following ways.
Words, sentences, or passages that you may have found challenging to understand the first time around were a little more familiar to you the second time around. For example, a Reading Comprehension passage about an arcane topic can be challenging to read the first time, but the second time you see that passage, you have already dealt with understanding that topic, and you will have retained some of what you learned the first time you read the passage. So, the second time you read it, you will understand it more easily and more thoroughly.
Not only does familiarity make comprehension easier, it reduces stress, and reduced stress can result in better performance and a higher score.
Finally, even if you don't fully recall which choice is the correct answer to a question, on some level, you recall the pattern of the question and what made that choice correct, and other choices incorrect. So, when you answer a repeated question, even if you don't fully recall what the correct answer is, you are more likely to choose the correct answer rather than a trap choice than you would be when seeing a fresh question.
So, while inflation may not entirely explain the increase in your score, it probably explains at least some of the increase, and could explain most or all of the increase in your score.
By the way, on multiple occasions, I have had people tell me how high they were scoring on practice tests, take the real thing and score much lower, and only then tell me that the practice tests on which they had scored so much higher than they did on the real thing were repeats.
Since taking a repeated practice test not only tends to generate inflated scores but also does not accurately duplicate the somewhat stressful experience of taking the GMAT, taking a repeated practice test is, in many cases, not even good practice, especially if the person using the practice test has used it more than once previously.