I tried to look at ERXPO, but wasn't flexible enough. If it's there, it'll likely be covered on the chain case side. So, hopefully a tell tale sign will be on the tunnel side.
Polaris put the parts diagram up for the 2021 sleds. The chain case and bulkhead parts are the exact same as 2020, so there won't be any signs of a tunnel dump. Looks like a whole new casting will be made for that side.