Interesting. That's not a boxcar lock, it's a switch lock. It's also made identically to UP locks. C&S switch locks fit UP locks all the way to the end system wide. Here are two very similar C&S locks. The one on the right came from Sam Speas, who brought it back from Como as a souvenir in 1937.
He may not know it's a switch lock, but for all I know, he may not be too far off on it's value.