That's the only way I found to claim mine. First I ran

    komodod -ac_name=BTCH -ac_supply=20998641 -addnode=78.47.196.146

to create the BTCH fullnode directory. After it synced, I tried to do importprivkey for one of my hush addresses. But that failed saying the key format was invalid. So I stopped komodod and replaced the generated wallet.dat with a copy of the wallet.dat from my hush fullnode and then ran it again with -upgradewallet:

    komodod -ac_name=BTCH -ac_supply=20998641 -addnode=78.47.196.146 -upgradewallet

That worked.

I set that upgraded wallet.dat aside and then did a similar process with the wallet.dat from my bitcoin full node. For each utxo I did dumpprivkey. These were now in the valid format. I went back to the first upgraded wallet (from hush) and successfully imported the BTC priv keys.