Ricardo:
Those are short versions of the full specification name. You can create an Invoice with a very long name (i.e. "OE$Invoice for All USA Customers except Texas"). But Adagio isn't going to store that full length name. It has a field 8 characters long and stores a shortened version of the name. Having longer fields would slow performance.

It takes the first 6 characters of the name and adds "~1" to the end (the name above would become "OE$INV~1"). If there were another file with the same 6 leading characters, it gets "~2" on the end. This is the same technique that DOS used to use (and maybe still does) to name files with more than 8 characters.

So you should look for a file that starts with "OE$NBT". The other one looks odd since it doesn't have a $ sign in the name. Adagio recognizes OE specification files because they have a $ sign in the 3rd position.