Can anyone else confirm the two different lables are the same product?

I don't know what you mean by two different labels but both jars of mustard I ordered tasted exactly the same

what are the ingredients?

Sure sorry But it did not last long. I suppose it has ground mustard seed, honey, oh and super yummies in it.

Does the mustard come with a sell-by or use-by expiration date? Also, do you know how long an unopened jar would stay good?

Yes, this mustard has an expiration date on it (we purchased our current jar back in February and the expiration date is August 2019. Do you mean how long an OPENED jar would stay good? After opening you keep it in the refrigerator - we use our a lot so can't really answer how long it lasts! If you do mean how long an UNOPENED jar would stay good - I would say as long as you are within the expiration date you are OK.... (personally, I do not keep things that have expired, even if they are unopened.

I notice one has a light label and the other label is black. Is it the same?

I was wondering the sam thing but I don't think there is a difference. I've purchased both. I'm telling you, this stuff is so good I would eat it on dog food ;) Hope that helps.