actually, I expect it was the newpaper that blurred the plate. I remember the radio giving out the car registration number, along with the description of the vehicle.

That seems sort of silly...why would you blur the very information that might help solve the crime, especially when it had already been released over the radio?

Might be a "quality of image" issue rather than an "intentional obfuscation" issue.

Of course, if the museum had been attempting not to have it discovered that it had a fake ... curiouser and curiouser.

Things like this are often stolen 'on order' as well, so there is high chance it was 'sold' per se before they even stole it.