I think pre-1953 XK120s didn't have the turn signals on top of the fender but from '53 on they did, continuing thru production of the 150 (I think).
I've never seen the chrome type in your photo of the silver car but I'm certainly not an expert, just a classic sports car enthusiast. Here's a '53 with turn signals similar to the one Bill posted, although he's already said his photo isn't of a 120/140/1...
