Rolex usually does incremental changes to their models, minor details in many cases so that the model lineage remains evolutionary rather than revolutionary.
It’s like taking 2 steps forward and 1 step back, but the latter was more to avoid alienating owners of the now-discontinued model. Owners of 116613LB would be glad that they had the gold/yellow wordings and gold crown while owners of 126613LB would gush over the slimmer lugs and longer power reserves.
To people outside of the watch circle, they only know it’s a Rolex.