With poppies it held to gat a photo of the spent flower heads or at least a flower bud. Papaver argemone has black at the centre of the flower, which is missing in this image, hence I think P. aculeatum is more likely
Richardson & Richardson Weeds of the South-East has a photo of Papaver argemone without the black base but says the flowers are dark red sometimes with a dark spot, while Papaver aculeatum is orange-red. P. aculeatum is covered with prickly bristles and P. argemone is stiffly hairy.