Jack - That's a spectacular reference; I've not seen it before. I don't believe Colonel Smith's report made it into the "Official Records" and it does give some credence to the Port Hudson Veterans' claims of Whitworths being there.
So, Col. Smith should have known what guns were under his command (a 'plus'), but likely he didn't have his records with him in prison (a 'minus'). Though the Whitworths are described as "small", their projectile weight is also given (12-pound), which shows that size is relative. The report also gives a date, May 8, which was after Gregg's Brigade (and Capt. Bledsoe) had left for Jackson Mississippi, so the Whitworths that may have been at Port Hudson were left behind.
John