First time buyer, thoughts on a Datejust

[JP365]

I'm turning 50 in July and decided to buy a used Datejust. I've pretty much decided on either a 16030, 16014, or a 16220, 16234. I know I want a silver dial and a jubilee bracelet. I do not want to spend over $5500 before taxes. At Wingate in Texas, I can get either a 16014 for $5,000 + tax and shipping, or a 16224 for $5,500 + tax and shipping. Illinois is one of those states where you must declare tax-free purchases from other states on your 1040, so I will have to pay 10.25% in the end. Locally I can get a 16220 for $6,100 including taxes from Howard Frum. The problem with the one at Frum is that it has a black dial. They will swap out the black dial for an authentic 16220 silver dial and keep the black one. None of these watches come with box and papers. All of them have a one year warranty against defects.
Questions:
1) No pics of the one at Frum, but what are your thoughts on the watches at Wingate? I can't post links because this is my first Forum post, but the stock numbers are C49718 for the 16014 and C38291 for the 16234
2) I think the prices are fair. What do you think?
3) Is switching the dial a big deal? Part of me thinks it will impact the price/value but the other part of me is completely fine with it.
4) Experiences with either of these sellers?

Thanks for your input.