The only way to know for sure is to see the screens. You can ask people selling them on Ebay to open the box and check but many may not do this because then, they say, they must sell the item as used and get less money. I said they could just say in the description that the box was opened just for inspection purposes only but, I'm not going to risk anyone reporting me for trying to do anything underhanded since one seller was suggesting I was asking them to lie or something about the device being new after the box was opened to turn the screens on. Yikes.
After all, the units that have confirmed upper or Dual IPS screens go for a lot more money. It would behoove the sellers to open and check and just list that in their auction as opened just to ensure the device turned on but...who am I to dictate their business? But, it doesn't hurt the ask if they could check for you. All they can say is no.
I've been trying to contact a few people selling dozens of new 3ds units on Ebay. So far not many are interested although I did find one that was checking screens and clearly marking their auctions, although they didn't have any Galaxy models currently, but will be getting Pikachu's come Friday and will check before they list. They offer their dual IPS units around $400-$450 brand new out of the box since they open and check the screens. Why wouldn't you, knowing you could get double the price?
Guaranteed dual IPS usually go for around $300-400 but there is a used one on ebay selling now for $200 which I am sure will be gone today:
I also found another seller willing to check on the Pikachus come Friday but I think they want more than my offer of $400 if they find a dual IPS unit. They are selling their unopened/unchecked units for $435 so...I think I may be out of luck there. I am offering $400 to find a dual IPS Pikachu or my Nintendo Switch in trade, but no bites yet. Still looking though and feeling out the scalpers on ebay. I feel anywhere between 300-$400 is fair since the sellers make a good profit and the buyer gets a confirmed unit they want and willing to pay for. Even used dual IPS units are selling for at least list price. I don't know why anyone needs to be more greedy than double list for a new unit but I'll keep trying.
I wish I could be of more assistance regarding the Galaxy but even the serial numbers people have been tracking on Reddit for that model have proven to be random screens, and most being dual TN.
This is tempting the crap out of me: