No Chris it's not, I thought the brown was filler but it's possibly a base paint. The picture is little deceptive as there's not much bare metal....it was painted cheaply and amateurish to cover up a few dents...
I'd just look for an original mudguard surround and attach that- doesn't matter if its rusty or not. Adds to the bike IMO and detracts from the damage/ bad respray area.
You can have this, good nick but modern and too blingy IMO also you can't have the AA badge (sentimental value)
Or this which I think would look ok, it's an original I think,came off a '66 Eibar I restored a few years ago. It's beat up but would look ok on yours.
Any road, just let me know you can have one for the price of postage.