I'm not sure why you just didn't buy an OCS stamp or two here:
https://crypto.post.at/onchainshop/owlcatz.c.cryptostamp.ethI think taciturn is saying you need an OCS stamp in your collection. Not sure about imported physicals. I do it in reverse. Buy onchain, then have the physicals sent to me via metamask. I don't recall it being super expensive, but maybe it was. The ETH network is really shitty lately, so many shit-tokens/contracts lol.