Thank you. I'll look that up when I get on my big computer later, and see if it lines up. I'm thinking the grower just made a mistake and mislabeled and sent the wrong shrub. It's not like you can tell them apart when they are bare root. I know there are different varieties of lilac but the ones I've seen have had similarly shaped leaves, and this one doesn't look like a lilac.
The leaves look more similar to a weigela than to lilac, but I'm not convinced that's what they are. I have had it for a few years now, but it has grown more this year than in any other one year, although so have the lilacs. Thus far, it hasn't flowered. If it turns out to be a flowering shrub, the answer might come in the flower.
As it turns out, they weren't wrong. It is a lilac. Although the leaves are entirely different from any other lilacs I have seen, it flowered for the first time this year - only one cluster - but it does look like a lilac cluster.