Colt mamufactures (or did) the 1/7 H BAR in both chrome and non-chrome versions. I think that it depends on the mfg. date, since the newer ones don't seem to be chromed. I have a non-chromed version and a good friend has a chrome-bored one with a lower ser. no. Both barrels are identically marked, so that doesn't help. They both came from MT6601 A2 versions. A visual inspection will tell you in a NY minute if it's chromed, if you know what to look for!
A famous and sucessful AR highpower shooter once remarked in his book that accurate chrome-lined barrels are only accurate in spite of the fact that they're chromed, not ever because of it!
A lot of the answer depends on what the particular shooter accepts as accurate. The tactical rifle community could never accept a sniper rifle with a chrome bore until FN realeased their SPR (Special Police Rifle), using barrels made on the same line as their 7.62 MG!
They developed an industrial process (at great expense) that is secret at this time, that allows them to be able to deposit the layer of industrial hard chrome that lines their barrel to an unbefore-known tolerance. The inability to hold these very fine tolerances is what killed the chrome bore in the past.