Colt offered 2 different versions of the Ported Anaconda.
The most notable one is the 8 Inch Ported model which has 5 holes drilled on each side of the barrel. These were made by Colts Custom Shop and they sported the standard accro red ramp and white outline sights.
The less commonly seen model is the one that is a true all out "Custom Anaconda". This version will have the single slot porting, a smoothed, contoured, and mirror polished trigger and a action job. This model was fitted with the Elliason Front and Rear sights. Colt Subcontracted Mag Na Port to port these barrels. They probably sent them 1000 barrels and then they were built inhouse at Colt.
Addendum:
Colt also made a 6" Custom Shop anaconda with 4 round holes drilled instead of 5. The 8 inch model was mass produced and there are many, the 6 Inch model rarely shows itself for sale.
*I have never seen nor heard of a 4" or 5" Anaconda with the round porting.