Even a year ago, Rolls-Royce shares had already been on the up for years, but someone who invested then could still be sitting pretty today. A gain of 41% means that £3,000 invested 12 months back would now have a value of £4,230. Remember, though, that someone who invested a year ago would now be earning a higher yield because of the lower price of Rolls-Royce shares back then. There could be more still to comeThe soaring Rolls-Royce share price has not come about by accident. Here's my concernHowever, I have no plans to add Rolls-Royce shares back into my portfolio at the current price.