I just purchased a 915 D2 "demo" from a major golf retailer. The shaft is the Diamana 'ilima 61g, Regular flex. After doing some research, it appears this might actually be a shaft from a 910D2. I should have asked questions at the store because the grip was not a stock grip, but I was in a hurry, the head was in perfect shape and it was 20% off. The price tag which is still on the shaft clearly says "DEMO". I think the shaft will be right for me at 65 years old and a 90 mph swing speed, but I feel like they duped me and that I should go back and ask for some kind of credit because the shaft is 7 years old. Any thoughts?