judging only from this picture....
i have seen original period COLTs, in brand new condition, and i tend to think that Turn bull case hardening is "overdone", i mean, brigther than originals, and more colorful...
original COLT casehardenings, specially for ARMY ISSUE revolvers, was less brighter and less colorful...with more browns than greens or blues..
as well as the blueing, in cylinder and barrel, was not so bright....in both the rust blueing revolvers, like many supplied to US ARMY, and the civilian ones, with heat blueing.
if you take a look at BERETTAS (made by UBERTI) they have a casehardening and blueing that rivals TURN BULL...at half the price
this is the ugliest i found in the SHOT SHOW in 2010...
modern Colts have a better casehardening, more tobacco like, with less bright as they did in the past...take a look also at the casehardening of my belgian CENTAURE 1860 on top of picture....making a good casehardening is no longer a secret...it rivals COLT..
as for other guns, like Smith & Wesson Russians, all have in common the same....the blueing, done by heat blueing, was quite moderate in bright, as it was more practical for the user...
judging only by pictures, i dont think TURNBULL does period correct blueing as the states...he uses more or less the same procedures, but seem "overdone".
all the best