Did Irnerius teach ca. 1125-1130 at the same time as Gratianus?

Saint Omer, Bibliothèque muncipale 453, fol. 10r
Bishop Gratian Teaching

St. Gall Stiftsbibliothek 673

33 Causae

(1050 canons) (ca. 1125)

St Gall, Stiftsbibliothek 673, fol. 144

Melodie Harris Eichbauer, "St. Gall, Stiftsbibliothek 673

and the Early Redactions of Gratian's Decretum," Bulletin of Medieval Canon Law 27 (2007) 105-139