The following link
http://tinyurl.com/dfk5ng show a small image of the A/craft flown by Weiss. As you can see there is no W.Nr. Listed. Not sure if you already have these details
"Black 10" Fw 190 A-8 W. Nr. not known
Pilot: Robert Weiss Stab III. JG 54 June 1944 Villacoublay France
This is the machine of noted Knight's Cross holder Hptm. Robert "Bazi" Weiss,
Gruppenkommandeur (II. Gruppe). The small "Black 10" is noteworthy.
This link
http://users.hol.gr/~nowi/luftprof/jg54/jg54.html also shows a coloured image of the same aircraft
Kind regards
Ross