The best I can find by all reports, the 1.7 Ghz mid '13 and early '14 are the exact same "identical" hardware.
The early '14 with the 1.4 Ghz chip is the exact same hardware except for the 1.4 CPU vs the 1.3 CPU. There were no other changes...
Other than the price being dropped by $100 on both the above machines.
Without heading to an Apple Store and checking the models on display and with multiple reports...
I can only suggest that the 1.7 Ghz model currently being sold is, in fact, still the mid '13 model and there is no such thing as an early '14 model with the 1.7 as is being reported by both everymac and MacTracker. Apple did not quit making this model on April 29, 2014 and start making a new model as both of those report.
While Apple did update the CPU in the lower end model - discontinuing the 1.3 and beginning the use of the 1.4 Ghz CPU, Apple did not discontinue the mid '13 with the 1.7, but continued making the exact same model with no differences other than a retail price drop. The 1.7 is not a new model for 2014.
I could be wrong and if Apple did update the firmware even though it is the exact same hardware, it would appear that at least one of the assembly lines is still using the older firmware. Personally doubt it, have never seen Apple start calling a particular model by a newer name. The late '12 Mac Mini did not become a '13 or '14 model just because they were still selling it in those years. The Mini was still a late '12 model even if manufactured and sold as new in October of 2014.