If it helps I have a box here of 91PX that looks like the small boxes in your picture. It has a glue on sticker that sort of seals the box which states made in USA. Box also has oregonchain.com on it which now redirects too oregonproducts.com/en
I don't know which products have changed over time.
This stuff I have does not have blued cutters.
For amusement looking at the back of the box and the sharpening instructions broken down to round ground chisel which has no symbol, chamfer chisel which gets a tm symbol and Micro chisel which gets the R in a circle symbol.
I see 91P on the back in the chamfer chisel row. How is it different from 91PX? Now there is 91 PX and 91pxl both bumper drive link one in the control cut family and one in the advance cut family.
It shows 90sg which is the bumper tie strap 0.043 gauge stuff that I doubt has been out for a while.
