I haven't been able to get my hands on any of the Harbor Freight blades, but I did buy a big lot of 45mm blades on eBay. So I have 50 - well 49 now - brand new name brand Olfa blades happily hanging on the inside of my fabric cabinet door.
BTW I paid $31 including shipping for my lot. Sometimes when you are not able to find one thing, you find something even better.