When Texas rigging does the hook have to lay in the “hook slot”? After I catch a fish and the bait gets turn up I wanna flip flop the hook to the other side. Does it have a negative impact?

I don’t think those hooks slots are critical. Other baits have them molded in as well. Especially craws. I wouldn’t over think those slots because your terminal tackle may vary. 

Nope.

I always treated it like a hook slot like a fluke and rigged it as such. Just keep rotating position- it’s fine

Hook slot isn't critical. It helps a little bit keeping the bait weedless, but it'd work just as good the other way, too.  

Nope x2

Not critical an any way. Just skin hook the point on the other side.

10 hours ago, DitchPanda said:

Not critical an any way. Just skin hook the point on the other side.

Sometimes Texposing the hook is better at weedless than using the slot.