FYI, 2 VERY good associations are alca AND wclca,they have great info on some of these and a lot of other locks. This is from a WCLCA issue that is quite informative. The yearly dues are very reasonable too,for both assoc.
Click image for larger version.  Name: crown lock 2.jpg  Views: 4  Size: 1.47 MB  ID: 20015Click image for larger version.  Name: crown lock 3.jpg  Views: 7  Size: 1.28 MB  ID: 20016 tried to scan page,but it would not upload, Maybe you can zoom these up to read.
It says no info on the F crown . this was 2016 issue
hope this helps