Seems you’re correct! The cockpit does bulge out further than that of the Stranraer, should have spotted that.
I’ve heard tell that this photograph may very well be a propaganda fake, a construct in order to bolster the perception of the Luftwaffe. Could well be, but even if it’s genuine, I know of no other direct combat involving the Stranraer.
I think this is where the only route to knowing for sure would be anyone knowing of specific combat logs/ personal diary mentions.