The terms custom and customized are very complcated to discern but also not really worth worrying about.
For instance a factory could receive an order from a company or distributor to swap out the sheepfoot blade of the their normal sowbelly for a wharncliffe blade. It would be a "Custom Order" something they don't normally make. Or an individual may hand make knives to his specifications or others. This too, would be custom, even if he only made one particular design, over and over.
Customized is when you alter your own knife or when a knife maker alters an existing pattern to meet your wishes or his/her own fancy. ( For instance the enormous number of Buck 110s that get new scales, Damascus blades, or other after factory alterations by some world class designers)
That's what I use to figure out custom vs. customized but I always leave lots of wiggle room.
But in the end I think this is all just semantics and a moot point. The bottom line for me is "like" If you like the knife and you thinks it is worth the price, does it matter if it is factory, handmade, custom, customized, whatever?