most of the seeds inside a Yuzu are likely to be clones of the parent plant, since Yuzu is a polyembryonic citrus cultivar
However, be aware that a seedling grown from a Yuzu seed will not necessarily always end up being another Yuzu. The Yuzu could have been pollinated by other citrus in the vicinity. Even if this is the case it will still likely turn out to be something interesting and worthwhile to grow, because there are many flavorful citrus varieties in Japan that are believed to be Yuzu hybrids.