Different Passing Mark for Pre-Test?

With the standard options no. This is because it is designed that if you pass the pre-test you will get credit for the post test and not need to take it.

However, with our master pages you can create a custom End of Module screen. This is the screen that will show up prior to taking a test (if no direct take test button is added - though for pre-test you might just have it launch automatically which is effectively skipping seeing this screen before a test) and after taking a test.

This screen can be customized using variables and based on the variables for the pre-test score you could display messages that tell them what you want, even though from a system standpoint it wouldn't be a pass. 

Depending on if you want a lower or higher bar, you would then need to account for that with the rest of your project design, but your key gateway to meeting this need is through a customized end of module screen and the use of system variables.

Depending on what your goals are, you could also consider publishing the course twice* and leveraging your LMS as part of the equation. You could publish it once as a Course and once as an Assessment.

These are available on the Type drop down on the Project Properties, which you can access by selecting the triangle beside the Project name in the upper bar of the interface then selecting Properties.  

The Assessment type will present only the test questions to the learner (the learning content pages are suppressed), so this can be used as the pretest in your LMS. When you publish the Assessment, set the course pass mark to 100%.

In the LMS, set the Assessment as the first of two courses in a curriculum (the language of your LMS will vary) ahead of the Course version. You should then be able to use your LMS settings to control the behaviour of the curriculum to allow the Lerner to test out of the Course version if they meet the Assessment's 100% pass grade.

An additional advantage of this approach is that you will have two different sets of data to run reports on in the LMS. If the one SCORM package has both the pretest and post-test activity, the LMS will only be recording one test score with no distinction between pre- and post-testing. 

* A variation on the info above would be to make a shared copy of the Course and set the copy as an Assessment and publishing it, rather than publishing the original Course twice and having to change the settings. This might be better for "housekeeping" processes.