^ What he said. There would be no way by LOOKING at the PCM to know it's an aftermarket/performance PCM. Performance PCMs ARE stock PCMs that have been reflashed with the performance tables. That's why you have to send in your stock PCM as a core to the company you buy your performance PCM from.
All they will most likely look for is a cold air intake, headers, a turbo or supercharger added to an otherwise n/a car, etc. I very highly doubt they're going to get someone knowledgeable enough to plug in a lap top, and have a way to realize the tables have been modified from stock.
