They do both early and late versions

35075 is the early and 35137 is the late.

Different turrets with different main guns. Late having a larger turret with larger main gun than the early.

Yeah, to elaborate on what the guys already said you have the early version with a lower velocity 57mm gun and the later Shinhoto with a new turret and a higher velocity 47mm. There were a few other improvements thoughout the history of the tank including bolted-on armour plate to the front giving a slight improvement to the biggest problem of the tank- it's weak protection. The Type 1 that entered service near the end of the war was largely just a moderately improved version of the Type 97.

http://www.tanks-encyclopedia.com/ww2/jap/Type_97_Chi-Ha_Shinhoto.php