That I couldn't answer, 64stang. Usually cowling would be constructed unless it was a kit. Is there any importance to whether the cowl is a premanufactured one or not? I'd think the plans would indicate the construction thereof. Since AFAIK
the cowl had rocker arm cover dimples on it, they would be difficult to duplicate in metal stamping of the day. Since this was offered as a magazine scratch build, I'd think it would be built up, may have had a sheet metal component to it such as Walt Musciano used to do for the "barrel" portion.
You've selected a neat scale cabin to model though. I've always liked the lines of the Reliant.