Could commercial yards build sloops instead of Flowers?

Could the commercial yards that built Flower-class Corvettes have built sloops instead?

Yes, but naval-standard sloops would take longer and require more capacity, so they could not match the simpler Flowers' wartime production rate.

The physical size of a sloop did not automatically exclude smaller commercial yards, especially if construction began in peacetime. The decisive difference was the standard of construction and equipment: sloops were full naval warships, whereas the Flower used a simpler commercial basis already selected before the war. Commercial yards could produce the corvette with machinery, methods, and labor they already understood. Building sloops in the same facilities was possible, but it would not yield escorts at the same speed once wartime expansion began.