Hey!
The first rifle I ever bought was a Marlin .444 in it's 18.5" barrel version. It's purpose was Barrenlands Grizzly protection up north of the Arctic Circle in Nunavut. It did it's job extremely well and I can definitely attest to it's sub 50m knockdown power. Hit something with it and it WILL go down... I still have the rifle and I still shoot it on occasion, but not a lot. It's expensive to feed ammo to and the light 18.5" version can pack a really mean punch to those of the slender persuasion. I still pack mine with me when in the bush, though, and it's still my choice for a woods-carry rifle due to the knockdown power and size of it. A similar cartridge, the 45-70, would be another choice, but the ballistics aren't quite the same. I prefer the Hornady LeverEvolution rounds myself.
I've never scoped this rifle as it's always been a swing-and-pull-the-trigger gun for those "oh crap" moments on trails, out fishing or at work. I suppose you COULD scope it, but make sure you're getting beefy enough glass that can take the pounding. If you're thinking of getting one for plinking... get a strap on shoulder pad at the same time, lol! 20 rounds of .444 and you'll be sore. It's fun as heck though!
Not sure where you could get a blued one as I haven't seen any since Russell Sporting Goods got bought by Wholesale Sports in Calgary. I see the stainless versions sometimes, but they're a little pricier and not as nice looking imho. I think I might have paid ~$450 at the time I bought mine, but that was quite a few years ago...
Fwiw, I don't "need" mine anymore as I don't work in the far Arctic anymore. Now I mostly travel internationally and if danger exists I have guards. I still keep the rifle though. It's a great range conversation piece, has some history with me and generally raises some eyebrows at the sight of the .444 cartridge when people think it's a 30-30, lol! It's also never misfed, never FTF'd and never let me down even in -50C. I love it and can't part with it,
As far as the older models go... I couldn't tell you. I don't know a LOT about the history of the .444 and all it's different flavors, just that it's comparable to the 45-70's. I didn't want a Winchester at the time I needed the rifle and I'd always loved my Marlin's.
Cheers!