Absolutely not!Where the phones are manufactured should be logged as well. Maybe there is a pattern with the factories.
I got my first 6S Plus through Apple and their failed upgrade program (had to buy outright even with my good credit), placed an order with T-Mobile the very same day through their Jump on Demand. Got the new phone in 3! days. Since they offer each model $100 cheaper I decided to go with the 128GB instead. The first one was 64, both Space Gray, both factory C3, both week 37. The first one is Samsung, the other one is TSMC. There is no pattern!