The WNMHGB phaser rifle DID have a crosshairs on the back of the "tower".
This is a HMS Studios replica showing the crosshairs
YOu can also see it on this screencap from the ep (just not as clearly)
On the question of the OP: think of the relationship between the Type 1 and 2 as being a little like a Baretta 93r. The Type 2 is the extended mag add on only.
There has been some speculation that at one time the Type 3/rifle was supposed to be done up with extensions for the pistol as well (adding a stock and maybe a barrel extension.
The original version of the "sniper" rifle in ST VI was built this way off of the "assault phaser", before they changed props.