I mean it's possible, P0441, P0456, and P0455 are not limited to the Gas Cap; that's just a very likely candidate.
I also wouldn't entirely fault Toyota for that, you'd be surprised how a lot of those hoses tend to glue themselves onto their fittings naturally unless they're high-pressure so a clamp may not have been as important on that side of the VSV.
That being said, adding a clamp because 11yr old rubber hose is maybe not gripping as tightly as it should? Not gonna hurt anything.
