Displaying single post pages differently in specific categories

Hi. I was wondering how to call a custom template using single.php as a main gateway. I made two backup single.php files, and renamed them to the categories I want to display the regular theme. I brought the Review Site plug-in, and I need these two specific categories to display the normal theme, and not the stars, positive/negatives reviews, etc. So, I have this code as my main single.php file:
<?php
$post = $wp_query->post;
if (in_category(‘6’) ) {
include(“experiences.php”);

} elseif (in_category(‘7’) ) {
include(“blab.php”);

} else {
include(“first.php”);
}
?>
This works, however, it skips the previous two categories and heads straight to first.php. Anyone know how I can call the first two categories before first.php? Thanks ahead!