I've done this a few of times with good results. With unbent rims, truing is no different than using new rims. However, its hard sometimes to detect a slightly bent rim until you are well into the build and are finding it hard to get things dialed in. In one recent case, I had the whole wheel laced up before determing that the rim was bent (to get the wheel true, I wound up with a really tight spoke on one side, and really loose one on the other). So I disassembled and started over with a different rim. Also, take a close look for cracks around eyelets; they can be really small hard to see when the rim isn't under tension.