Yep. Some OEM machines still use reputable mobo on their machines. I know I've seen HP machines with gigabyte boards (if memory serves me correctly).
Sadly, I don't ever recall Dell using brand name boards but if it's an XPS Dell then they probably would.
Best suggestion is to check. If it's a brand name board you might be able to load a bios from the mobo manufacture (MSI, Asus, ect).