This is how the Chip and Dale costumes changed in the parks.
The original Chip and Dale costumes from 1955
In the 1960s, they look just identical probably to confuse guests from knowing if one of them is Chip or Dale.
The 1970s Chip and Dale costumes had larger eyes and larger heads with extra neck fabric.
The current Chip and Dale costumes, seen since the early 1980's get new smaller heads and ditch the extra neck fabric. Their hands are now four-fingered.
versions of Chip and Dale, seen in various live shows. Notice that Dale has a hairpiece on the top just like his animated version. They also are slightly shaggier.