A shufti in the Key Cards might indicate if it had a rebuild serial number. In all probabilty, the WD stock number for an M20 rear mudguard never changed and valance or not, it would have been stocked, issued and fitted regardless.
Rebuild serial number indeed: C1411417. So it is indeed a mishmash.
If you want to know more about war time rebuilds, please check this thread that I made on HMVF.
