Yes, it is a regional dialect. However, it's a dialect is only prominent for words ending in -n.
In the majority of dialects, a word ending in -n is alveolar (your basic "n" sound in English, such as "begin").
However, is some dialects, the final -n sound is articulated further back in the mouth. At it's most extreme, it can become a velar nasal sound, sound similar "long" or "bang".
However, this distincion isn't quite as pronounced as the question implies--there's no articulated "g" sound on the end of the words. But it does seem to carry that velar nasal sound we see in "long" or "song".
This velar "-n" is common in some parts of Spain, the Caribbean, some Central American dialects, as well as coastal areas of some countries in South America.
See also: Wikipedia: velar -n