What's with the "A" Suffix and "W" Suffix??

[w30bob]

Hi Guys,

 Anybody know what the "A" suffix after the "Model 17" and the "W" suffix after the SN is about?  Usually the "A" or "B" is part of the data plate, and not an afterthought stamping.  And I have no idea what the "W" is telling me.  Anybody?

thanks,
bob

[undee70ss]

[MI Old Saw]

Can't say I have seen an 'A'. I have examples of the Phelon and Wico designations on some of my XL's.