[78-L] Added Blue Price Stickers on early Columbia Labels

[78records at cdbpdx.com]

Many of the early blue label Columbia records have a repricing label affixed to each side.  Most appear to be machine cut and applied while others seem to be cut out and applied by hand.  I recently found an older black label Columbia with the blue repricing sticker on each side.  
 
1)  Exactly how were these repricing labels applied?
 
 
2)  Blue repricing stickers on black labels?  Looks kind of weird.
 
Thanks!  CDB