Later models of the A6M3 had the folding wingtips not installed.
Nakajima produced the Sakae engine which had a two stage supercharger. The engine was longer and required the firewall to the rear by 8" / 20 cm. This caused the fuel tank to have to be reduced in size.
The larger engine resulted in changing the cowling to be more rounded and larger. Propeller was slightly larger.
The first two A6M3s produced had the folding wingtips but they were removed in the hopes to increase speed. This was to compensate for the heavier engine. It was hoped that the shorter wings would make the A6M3 more maneuverable, but this didn't happen.
In honor of Air Force General "Hap" Arnold the A6M3 Model 32 was called the "Hap." However, he did not appreciate the gesture and ordered the designation to be changed to "Hamp." After captured examples of the Model 32 were captured the name was revised to Zeke 32.