Resurrecting an old thread I found.

Is anyone still collecting data on serial numbers of 1894s that have the standard and improved lock?

On p.2 the difference in spacing is discussed. The lowest serial number with the improved lock discussed in the thread is 132037, which is a CEO Live Bird Gun discussed also in Semmers book on p.214-15 and pics on p.222-23 which book I have in my library.

My 1894 is also a CEO Live Bird Gun yet, serial is 132034.
Hope this helps.