Would I be able to get assistance in-store if I brought in an older case I plan to build into?

I'm planning a sleeper build using an HP Pavilion 9695C case from around the late 90s-early 2000s, and after some research I have a general idea of which parts to get and what would fit well. However, with it being an older, not-so-big case, I was hoping that if I brought it in I could get some help with figuring out how to make it all work without the thing overheating. Is this something that would be possible? I wouldn't be needing help actually building it since I can handle that on my own at home, it's mainly just making sure I get the correct things I need to get so I can build into it in the first place. I just want to make sure that this is possible before I make the 2 and a half hour drive up to the Sharonville location.

Any info would be awesome and greatly appreciated!