Unfortunately, that's a photochop.
You can see where the clone tool was used clumsily, and that's not even close to a sign font. Looks like one of the stock Windows sans serif fonts. Nor can you see the clear track the removeable letters would have to be sitting in.
I wished I'd had my camera with me for an actual sign error at a nearby McDonalds. It had said "Now hiring closers", but the C fell off, leaving it to proclaim "Now hiring losers".
