I'm skeptical of the value of expending the effort to make a new part with no functional difference and where the visible difference is so small as to not really matter.
That said, if this is the route we want to go down then 3847 should move to 3847b and 3847a should be new part variant.
That said, if this is the route we want to go down then 3847 should move to 3847b and 3847a should be new part variant.