New Hampshire reds are a breed derivation of RIRs (Meaning, they where bred from RIRs) and are basically, a bigger, lighter version of RIRs. As a consequence, they are better meat producers but they also produce fewer eggs.
I am not an expert and can not tell whether your hen is or is not an RIR or New Hampshire (other's might though) . However, both New Hapshires and RIRs may have black markings that may be shimmery (green/blue/purple accented)... It is actually common in both breeds for their plumage not be solid red/brown.