New to Linux. Short story is I didn't bother verifying my ISO due to it being downloaded directly off of Elementary's site and now I'm wondering if this was a mistake. Post installation is there any way to verify the integrity of this install? Thanks in advance.
If your installation is working, then there is probably little point in verification. The point of verifying the file is usually to check the iso file hasn't been corrupted during download. Corrupted downloads usually result in installation failures, so if you've managed to install elementary successfully, the iso file was probably valid.
Realistically, you'll only be able to verify post-installation if you kept the original iso file you downloaded, and follow the steps as documented.
If you didn't keep the iso file; in theory, depending on how you wrote the iso to your installation media, it may be possible to turn that back into an iso and then verify it. But there are a lot of potential ways that could go wrong and give you a false negative result, so I won't document that here.