Can nac (every other day to minimise potential reduced glutathione production)help chronic low level inflammation in the liver and perhaps gi tract?

Probably yes: It is impossible to say for certain, given the lack of research on this, but NAC has many health benefits and also increases glutathione, which is anti-inflammatory . I advise about 1200 mg of NAC/day- no point in limiting to every other day. See http://www.lef.org/magazine/2010/5/N-Acetyl-Cysteine/Page-01 & http://www.huffingtonpost.com/dr-mark-hyman/glutathione-the-mother-of_b_530494.html