Thank you @davpx for your fast responce. I know I can do it. The question, Although not plainly stated is, should I? I don't know if manually doing this will mess-up the upgrade of the indexers in the future.
That is indeed a valid concern. I have created the index in a mixed environment where some are 6.5 and some are 6.4 some are 6.3 and have experienced no issues. The only difference is that 6.5 will begin actually using it.