The acquisition of Kraus's excellent work on the uniforms and personal equipment of the Imperial German army sees this battalion enjoy a few refinements.
The main difference is the painting of sword knots in company/battalion colours - in this case with a white background to denote 1st battalion.
Here we have the second company, leading the fourth company:
As always, officers - both commissioned and non-commisssioned - followed their own rules:
For completeness, here are the rules of cap buttons.
These plates all come from Ruhl, M., Die Uniformen der Deutschen Armee, Volume 2, (Leipzig, 1899).