Thank you for all the responses. The dealer installed a 54" Edge Xtra deck, which JD doesn't list on their site. The Edge Xtra deck is ~$400 cheaper than the 54HC drive over deck without auto connect, add in auto connect and it is ~$700 more for the 54HC. The dealer told me JD doesn't advertise the Edge Xtra for the X700 series because they want people to pay for the more expensive deck. Since the X500/X300 use the Edge Xtra deck and are considered great mowing machines and I don't really need the auto connect, I went with the less expensive Edge Xtra deck. I also don't have a large lawn to mow, so long term durability of the 54HC vs 54 Edge Xtra shouldn't be an issue. I went with the X738 due to a steep hill and for snow plowing abilities.
I am still learning the ins and outs of the tractor/mower...I did some nice scalping yesterday

Need to figure out what height works best for my lawn, hills, etc. as well as how to adjust the wheels to their proper height.
Here are some pictures of the 54" Edge Xtra installed on the X738.