Not yet. The current version for Sandblast appliances is R77.30 (recommended the latest GA Jumbo Hotfix). However, unless you're using your Sandblast appliances also as "regular" Security Gateways (routing traffic for instance) I would not worry about that -while R77.30 is supported :)-
Also, note that you need R80.10 Security Management in order to manage a R80.10 Gateway or Sandblast Appliance 🙂
As a footnote, generally speaking, I recommend to upgrade the management server to R80.10 version. This way you will benefit from lot of management improvements and you will be ready for the upcoming upgrades of your Gateways. Also, if you are not already using R80.10 SmartEvent, I do recommend it.