No exactly. They offer 2-of-2 primarily, at least for their implementation with Blockstream. There is 2-of-3 but most would use 2-of-2 because it is what they are offered by default.

https://help.blockstream.com/hc/en-us/articles/900001391763-How-does-Blockstream-Green-s-multisig-security-work-

If you lose access to your 2FA method, or the Blockstream Green service becomes unavailable, then the account recovery process is different depending on the type of account you are using:

2-of-2 Bitcoin
Uses nLockTime

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Bitcoin Standard Account Recovery (nLockTime)

The recovery process for Bitcoin standard accounts requires pre-signed nLockTime transactions. If you have set an email address for recovery in your wallet’s settings, these nLockTime transactions will be emailed to you whenever you make a transaction.

Note: You must set an email address in advance to be able to recover a Bitcoin 2-of-2 account.
If you have not made any transactions within the timelock period (default 12 months), then the nLockTime transactions can be used to move your funds without requiring a signature from key 2 on the Blockstream servers.

To ensure that your wallet is always secured by 2FA, the app will request a redeposit for any funds that haven’t moved for the duration of the timelock period.