It says Imperial U
Prov RI A
Meanning Imperial knife co. Providence Rohde Island UAS
Where the word "Imperial" is stamped into the blade, just past it, VERTICALLY (up and down), is USA. The "A" you are referring to is the "A" in "USA".
The knife was made in the USA, in Providence, RI.
what it actually says is Providence, R I, If you look closer, you'll see that the A is part of USA running vertical to the other printing.