Yes. They will want a fresh sample on ER day. However, you may want to (depending on how much time you have before ER) have some samples frozen prior to ER day. That way, if something goes wrong (he's too nervous to produce, the sample comes out no good, what have you), you'll have a back up.
This. We had some frozen just as "insurance" in case DH had any issues the day off. It wasn't much to freeze and was worth the peace of mind. GL!