you can claim your share but it's really dependent on how willing BitGo to help.
in short, you need your private key combine with their private key to access the fund.
I read something about keytern.al as backup key (3rd key), you might want to ask BitGo directly about it
a thread about BitGo and keytern.al https://bitcointalksearch.org/topic/bitgocom-full-control-over-your-bitcoin-1795397
before claiming BCH or other fork coin, I strongly suggest you to move your BTC to another wallet (out of BitGo)
any wallet that you fully control the private key, better safe than sorry
Ok, roger that.
So can I place my BTC in my ledger now and still be able to reclaim my BCH eventually? Or does my BTC have to physically stay in that wallet until BCH is claimed? (Or is the history sufficient?)
Thanks so much for this insight.