Definately measure it to see if it's in spec.
Just recently I had my machinest measure a standard bore XR600 cylinder I've had kicking around for a number of years. It looked great. I figured I'd hone it and use the 10.8:1 compression Arias piston that came out of it (it looked great as well) and be good to go. Wrong! It was way out of spec in both size and roundness.
So the moral is, just because it looks good doesn't mean it is.