I would venture to say that with adequate moisture the peas and the canola could both do well, which will create harvest quality issues unless you plan on desiccating. I am not sure about yield implications if the peas are that far along.
Basagran Forte says it can be sprayed up to flowering. Hate to trample the crop and spend the $20-25/ac on the basagran if its not needed. I know that annual sow thistle seems to appear in my crop every year late in the summer, so not sure how competitive peas really are.