Yes it can make a difference to pressure & POI.
Variance of thickness of different manufacturers brass may well change the pressure of a given load in one make of brass to another.
How serious the change can be depends on how close you are to maximum propellant charge.
Work up the load for each manufacturers brass.
Ideally, stay with one manufacturers brass to achieve consistency.
Thanks for the info...I'm happy with the results my current brass gives and before anyone says it...yes if its not broken don't try and fix it...but I have this brass just sitting here so wondered if a tinker here and there may improve upon what I currently achieve.
I'll drop down in powder charge and work up and see what if any improvements there are