I own a 2014 with 11sp 105. See if they'll throw in the CG-R seat post. The new ones come with it and it really makes a difference on the very stiff SL4 Roubaix frame.
I think that's a fair price. They were around $3200 new if I recall correctly. The 10sp Ultegra groupset isn't as good as the new 11sp stuff IMO but that can be upgraded in the future for not a lot of money. Bear in mind that the Roubaix is probably due for a refresh next year.