A new store listing on AliExpress suggests that the new Switch 2 Joy-Con might be customisable; at least to a certain degree.
As highlighted by Stealth40k on Bluesky, a listing from Electronics-Dropshipping Store shows that the side panels on both Joy-Con can be removed and replaced with different colours. The two products up for grabs include the standard blue and orange colours; one mirroring the setup of the Switch 2 itself, and the other reversing the colours (so orange on the left, blue on the right).
It's an interesting concept, but we think it's probably worth stressing that Nintendo hasn't mentioned anything about customisation with the Joy-Con. With that in mind, we probably wouldn't advise you rush out and buy these – cheap as they are – since removing the side panels may well cause damage to the Joy-Con and void the warranty.
Having said that, it does look like the panels can simply be prised from the Joy-Con and clipped back into place; there are no screws or anything to keep them secure. It could be that Nintendo sees this as an opportunity to introduce customisation in a new way – kind of like the New 3DS.
Then again, we can't really see Nintendo passing up an opportunity to sell variants on the Joy-Con 2 at full price. Either way, then, this is definitely pretty cool, but we'd advise to just exercise caution for now.