The misidentity of the perf 12 1/2 37d is a pet stamp peeve of mine, I didn't chuckle at all when I saw the OP with an 1890's cds. It is only found for a few months in 1870.
The shade of a 37d is somewhat variable, partly due to them being 150 years old (under variable storage conditions) and partly due to variations in ink formula. The example I show here is as close to the "peak Indian red" as I've seen, hope the reproduction here does it justice.
I added a rule rather than a perf gauge so viewers could scale the image.
I'd also add that the cancel of the stamp I show is a NS grid oval, consistent with what you'd expect to see on genuine examples. Saint John 2R7, Pictou 2R30 and Truro 2R54 cancels confirm its use in NS / NB. Montreal dated examples are also known.
It's printed on a specific high-quality wove paper, I'll post a back scan in a few days.
I think the example shown with 2R7 cancel in thread is definitely an Indian Red too, have some concerns about perfs at bottom being recut (note how the cancel doesn't extend to edge, giving a halo effect) but I'd have to see in person to judge.