Call the County Sheriff and inquire. If, as I hear, the MS law has been changed to eliminate a holster has "concealing" a pistol, the County Mountie ought to confirm that.
Why would you ask a police officer that question? What guarantee do you have that the cop knows the law? Read some of the tons of stories of harassment by police against OCers in various states, and witness the sheer amount of ignorance or downright malice displayed by police officers when confronted with questions of statutory law. And most of all, why bother asking a cop, when the law is right at your fingertips!
http://www.lexisnexis.com/hottopics/mscode/
And now to address the middle part of your post. Mississippi law does not say
anything about whether a holster "conceals" a pistol. Concealment is not defined in the MS Code - the phrase "concealed in whole or in part" appears several times, but nowhere is "in part" defined (or "in whole", for that matter). The confusion by many is based either on hearsay (always a dangerous thing!), or on a justice's rambling in his concurring opinion on a MS Supreme Court case.
Now,
HB2 aims to remove the "in part" language from the MS Code, which will remove the ambiguity. It has not been passed and signed into law yet.