Differences Between the J H Williams S-50 vs S-50A Ratchets

[HOF]

I know the handle has a capital "A" stamped on the handle. Are there any other differences? I would think it would be an upgrade of some sort. Here is my S-50.

 

[HOF]

I picked up a Williams S-50A variant. After looking at some Williams catalogs and my new ratchet ... the pin that captures the S-150A plug is not installed nor is there a hole for the pin on the S-50A ratchet. This allows for the plug to be easily removed from the ratchet without full disassembly.