One way to tell “for sure” is to test it.
Pick a computer you can test with (your workstation?) and deploy an action to the computer.
Deploy an action with the Pre-Cache option selected. Give a good separation between when you deploy and when the Action should take effect.
Keep an eye on the BigFix Client Logs (I recommend a tool like the free version of Baretail). You should see it mention downloading the content. Once it has done so, you can go look through the __BESData folder to visually verify that the installer has been Pre-Cached on your endpoint.
NOTE: One thing to keep in mind, and @AlanM might be able to chime in here, if you do this to a Baseline, will it attempt to Pre-Cache ALL the content included in the Baseline, or only those items that are Relevant to your endpoint?