French reproof is a crown and R. I've owned one gun with that mark. I'd say Ted's right. Without the reproof mark, someone had the chambers punched but the gun was not submitted for reproof.
I thought that as well. Then I started to think about. Anyone who was foolish enough to fake a proof mark faced a prison visit. When they got out, no one in the business would be foolish enough to hire them.
So you have either a very greedy fool or some one at the proof house who goofed up. They were in a hurry to meet the boys at a Friday lunch....?
Pete