Presented below are some detailed photos of an authentic Star Trek: The Original Series midgrade pistol phaser prop of a style that is believed to have been introduced in the 3rd season of production. It features a highly detailed front silver nozzle (or "Photon Accelerator") and a black powerpack/hand grip section with an elongated central groove extending along the full length of the section ...
A phaser in this style is seen in the following screenshots from the 3rd season episode "Plato's Stepchildren"; which was first broadcast on Nov. 22, 1968 and is often remembered for its historic scene that contained the first interracial kiss shown on US television.
In the following screenshot from episode 76 "The CloudMinders", first broadcast on Feb. 28, 1969, Captain Kirk is shown with a midgrade phaser in this same style.
Most TOS phasers seen at auction; whether midgrade or stunt versions, feature hand grips that are similar in style to those found on the working or "Hero" pieces. One example of this style is shown below, and the reader is directed to a different article on this website, viewable at http://startrekpropauthority.blogspot.com/2008/08/star-trek-original-series-pistol.html to see a more comprehensive listing of Major Auction House phaser offerings.
The following screenshot from the episode "Dagger of the Mind" features a pistol phaser with a variant style of velcro placement; seen adhered to the blue/grey pistol body as opposed to its usual place on the side of the hand phaser unit.