No. Commissioning is productive work and requires the status to be approved and the engineer admitted in it. A visit to inspect the site without performing the work is a different activity, and its limits should be checked before any trip.
Approval first, then the wrenches
The temptation is real when a customer's plant is waiting and the subsidiary has already been paid. But an engineer who begins the commissioning work in the United States before his L-1B is approved and he is admitted in that status is working without authorization, which can affect the pending petition and future entries. What a Canadian citizen may do as a visitor is limited to activities such as attending meetings, observing and consulting with U.S.
colleagues, and the line between observing and doing is easily crossed on a plant floor. The safer sequence is to file the petition as soon as the sale is signed, request premium processing under the fee schedule if the schedule demands it, and have the subsidiary's staff perform preparatory work that does not need the proprietary procedure. Once approved, the engineer applies for admission at a port of entry with the approval notice.
If the customer's schedule cannot wait, that is a commercial problem to solve in the contract, not by adjusting the engineer's activities.