Yes but the GS register says:
The gas pipework in your rented property must also be kept in a safe condition. Installation pipework is not covered by the annual gas safety check, but both we and the HSE recommend that when you request a safety check, you ask your Gas Safe registered engineer to:
- Test for tightness on the whole gas system, including installation pipework
- Visually examine the pipework (so far as is reasonably practicable)
So not mandatory but probably a really good idea and more than likely to cover your bum, if anything goes wrong in the future?