Hi @dshort1988
There are two motherboards available for your model.
HP part #941884-001 (Description - MOTHERBOARD UMA i7-8550U 16GB) i.e. non Windows OS
HP part #941884-601 (Description - MOTHERBOARD UMA i7-8550U 16GB WIN) i.e. Windows OS
If you have no success searching for motherboards using the laptop's model number, search online for the ''HP part number only'', instead.
The part number should be located somewhere on the motherboard in your laptop, if you wish to verify which one you have now.
Here's the [http://h10032.www1.hp.com/ctg/Manual/c05811755.pdf|maintenance and service guide], taken from this support [https://support.hp.com/us-en/product/setup-user-guides/hp-spectre-13-ae000-x360-convertible-pc/model/18164678|webpage] for the laptop. Go to p.51 to view the procedure to remove/replace the system board