You are right. Knowing the State is important, but it is more important to know research methods. You have that one covered.
Start with this group, who come highly recommended. They have published Shreveport civil birth/death records. They can also recommend a researcher with Louisiana experience.
Go to the very bottom and email Judy (author and professional)!!
They have an African-American Special Interest Group (SIG) as well.
You might consider joining. There are many benefits to being a member of a local genealogical society. One being the opportunity to learn about 'taking up the cause' yourself, when your researcher has delivered the initial results.
Next, there is a group in Shreveport that have published Louisiana records.
Queries are free in their publication, but you will need to be specific. Who, What, Where and When - Names, Information needed, place and Time are important.
Save the link and keep this in mind for extending your research.
There are others in Louisiana and Texas (and the US really), that have Louisiana African American research experience - too many groups to name right now.
I'm sure the first link will help. If not, re-post here and I'll provide more options from local recommendations.