Correct.
If you follow the normal upgrade instructions.
https://www.ubbcentral.com/doc_upgrade7.phpWhich is what you should start with.
It tells you to upload all the files except for certain folders such as the styles folder. Also pay special attention to the part about the cache builders folder.
Then in addition the txt file in the zip has special instructions. Which you should always check for special requirements
In this case the txt file in the zip instructs you to upload only those two files to the styles folder not all of them.
Other than that go back to the generic upgrade document in the link above to finish .
BTW, Somebody has edited the generic document and added the note about the two style files for 7.5.7
