How to Set Up Source Engine-Style Inventory Scroll?

This is what I’m trying to get. (I’m working on a L4D fangame, so that’s why I’m trying to replicate this type of HUD.)

277378-inventory-2.png

I can definitely see where the bottom three could be easily based off of the same slot widget but I foresee the top three being a little bit more work. I’m guessing I should just build the base widget with all of the setups needed for every single slot and then have a check for which slot is actually used and disable everything that doesn’t pertain to that slot?