Fake ? Not fake ! Simply the same serial number as it came with...
Well......about repro/resto:
It's the same with everything else on a cab: do you leave it original or do you replace stuff ?
F.i. I see very little harm done in replacing the black vinyl on my SW. Nor do I see much trouble in replacing a lot of other stuff. Of course, the goal is always to first try to "revive" the original parts but sometimes they are either simple impossible to revive or they could be simply missing at all.
To replace the vinyl on the backdoor of my SW I had to remove those stickers. However careful I tried, it still didn't get better from the whole job....It's totally wrinkled now and to put it back on the machine would look totally out of place.
I see very little problems in putting a perfect looking copy of that serial sticker on it though.....it will maintain the tight look of the machine.
Now, of course, it _has_ to be perfect

@Etienne: of course I still have that pic in full res, I'll mail you. Not sure if scanning it in it's current condition is going to help a lot.... ?