No, I didn't even check with them. I had bought my car used from Autolenders and read on here that there is no specific part number regarding the divider in particular.
Having dealt with similar instances in the past (I've had a situation where a bumper plate bracket required the purchase of the full bumper) I figured I'd just be wasting my time since they'd likely just tell me I'd have to buy the entire cupholder assembly (I'm not paying dealer prices for all that just to get the plastic piece that clearly costs nearly nothing to produce).
That said, some on here have mentioned contacting their dealers about the issue, though I don't recall any success stories regarding getting one without the purchase of the full assembly. Your best bet is to check your local junkyard or online junkyard repository (there are sites that will search their various inventories for said part and then get back to you if they can locate one). Ebay was fruitless for me, the numerous times I checked resulted in nothing.
Some on here have gone through the process of buying the Japanese model's (known as the Honda Vezel over there) entire cupholder assembly as it is an overall better design that keeps cups secure with automatically adjusting braces for both the lower and upper portions of the cup. The US version, as far as I can see from pictures, just braces larger cups/bottles at the bottom and doesn't do much to stop them from tipping over the piece in question that my car was missing. The lower portion doesn't adjust to fit the cup either so more slender bottles/cups will slide around from what I can see looking at the design in pictures.
The implementation I've come up with solves this issue fairly well, since the brace I'd able to be placed far enough up in the holder that it prevents tipping. Items can still slide around the bottom of the area though so I may come up with something to divide the two areas a bit better. I'm hesitant to try this, as I feel ill likely be wasting money/performing a bunch of returns but Amazon sells a few cupholder separators that
look like they may fit quite well. One that comes to mind is for a Toyota Camry but I didn't bother buying one because even a millimeter or two difference in width would result in the piece being loose or not fitting at all. (Edit: here is a link if you're interested
https://smile.amazon.com/Trunknets-...&qid=1628736416&sprefix=cup+holder+sep&sr=8-4)
I'd imagine an individual with a 3D printer could probably make some and would have a decent customer base if they put them on Ebay/Amazon. It really makes NO sense that they don't sell the part individually online and is really just annoying considering the design wasn't very good in the first place.