Checking Dell's Facts about a Motherboard Purchase

I'm looking to buy a new motherboard that died in my son's XPS 2710 All-In-One (this is NOT a touch-screen model.) The motherboard that is in there now is Dell system board number 2XMCT, and it is dead for sure. It's three months past the warranty period, unfortunately. I have replaced many motherboards in the past, so I can definitely do the swap-out if I could find a compatible replacement motherboard.

Dell representatives have quoted me the outrageous price of $514.99 for a replacement 2XMCT motherboard.

However . . . the sales representative also quoted a price of $314.99 for a 3VTJ7 motherboard. The representative told me that the 3VTJ7 is "compatible" with my XPS 2710 All-in-One. But I didn't get the impression that the sales representative really took much time to make sure, and I don't want to buy it until I know it can work in my computer.

I looked at pictures of the 2XMCT and the 3VTJ7. The boards look identical in seemingly every detail.

Does anyone know what the difference might be between the two, if any? It raises a red flag that the 2XMCT costs $200 more, but perhaps the higher cost is simply a supply-and-demand metric.

Thanks for any insight that people can provide.