No, there is not, at least not that anyone has spoken of. After taking mine apart (blowing the warranty) I can see no way to do such a patch here. After removing two tiny screws, self tapping into plastic, sure to be a problem for some you can get the SS cover off:
On the right, at the bottom, you can see the soft seal you see peeking in. It's too soft I think to grip the stem and sits against the top (no room for a ring). The black bushing above that seal is where the 3 ribs guys call 'o-rings' (they're not really) that provide the fit. Stiff for a good grip on the correct size, at least for a while, but not compliant enough to adapt widely. That's a custom seal, I doubt Arizer will sell you one.
If you blow up the photo you can see the ribs at the top of the bore, above the threads that mate with the white plastic body.
Tight stem fit is not a supported feature, here or in Solo.
One other point, it was never intended for owners to venture in this far I think, there was a burr on the mouth of the SS cover that prevented me from putting it back on without filing and sanding.
OF