First, unless you truly understand how to read a home inspection report to find the critical issues, having a copy of the inspection(s) on file probably won't help you as much as you might think.
Second, although I also typically will ask for copies of any inspection/appraisal/survey reports on file, I do it more as a tactic to help me gauge how forthcoming a seller and his/her agent is. If the selling party balks or wants to delay, then indirectly they're telling me they're trying to hide something, so I instruct my inspectors/appraisers/surveyors to be more thorough and dig deeper.
Third, since you have no idea whether the seller hired a bozo who doesn't know how to conduct a proper inspection, it's much better for you to hire your own inspector. This way you get to interview and screen several of them until you find the right one for you. It's not enough to find a good inspector; you need to find one that can also thoroughly write up a report that you understand.