Guidance On Ux4 Post Card Condition

I have been going through some old stamps and postcards from my dad. I was under the assumption that the UX4 postcard was unused mint condition. I pulled it out of the mount and found printing on the back. This means used?
Any idea why that printing would be there? I have many other post cards and none with printing on the back like this. If someone could provide input on official condition I would appreciate it.

It is pre-printed, but not used. These are listed in the Scott Specialized catalog that way.

of perhaps more significance, this is definitely not a UX4, since it's a UX7.

Well that's disappointing, but correct when I look at the catalog. Thanks.