Yes, per the datasheet (page 2):
"Any of the supported 100 Gb QSFP28 direct attach cables can be used for the stacking links"
https://cloud.kapostcontent.net/pub/44317954-ef18-4082-8714-3b22a9540f32/x690-data-sheet.pdf?kui=t3jIjd3uJZgg-RyyxO3sWg
The QSFP28 LR4 cables are listed in the ordering information at the bottom of the datasheet.