All About Pocket Knives

When you see a NOS blade like this that has been heated up is that an indication that the blade has been restamped? I have seen other blades that also have shown evidence of heating and then there are other NOS blades that aren't?

https://www.ebay.com/itm/CASE-XX-TESTED ... SwUzJdo6hp

Bob, I saw that one along with several other vintage Case blades, some with similar burn marks and no hole in the tang, that the seller has for sale. The seller indicates that they also need to be reshaped and finished in order to be used for "repairs". I am wondering if they are old Case factory rejects that were never used or maybe?????