Just google "Stevens 44 1/2 rifle and you can learn everything you could desire.
Briefly, it was considered the strongest and best SS action made by Stevens. It was a totally different action from the 44, greatly improved. Frank De Haas spoke well of it in his classic "Single Shot Rifles", although he had numerous small criticisms. He said it could handle up to 50,000 PSI (His figure, not mine!) but it was not will suited to large diameter rounds (45-70) at higher pressures because of it's small diameter barrel shank.
It was made from about 1904 to 1916. With your four digit number you might have a first year gun. I couldn't find an actual figure of how many were made, just dates.
That 28-30 cartridge is quite interesting, and it was a favorite of Pope's. It looked almost identical to a 32-40. It fired a 120gr. bullet using 30 grains of black powder. Velocity was 1500. Google 28-30-120 Stevens.
I'm guessing it is worth a tidy sum, especially if the barrel IS a Pope. Would like to give you a number, but pictures would be priceless.
Hopefully, your rifle is factory original and as it was when it left Pope's shop. Its originality is a critical factor. If it has been screwed with, like the one for sale on Armslist, it is worth only a few hundred dollars. If unmodified, especially if you have accessories, perhaps thousands.
Pictures please.