As near as I can tell, the modern replicas are the same as the originals.
Dixie Catalogs have some very interesting tables in the back of them.
One of these in a 1980 catalog lists the original and replicas as being the same.
The loads for a few guns are:
.44 Colt Dragoon .453 ball, 40 grains FFFg
.44 Colt/Remington Army .453 ball, 28 grains FFFg
.36 Colt/Remington Navy .376 ball, 22 grains FFFg
.31 Colt/Remington Pocket .321 ball, 15 grains FFFg
They didn't give the .44 Colt Walker load but I think it was around 45-50 grains of FFFg.
The 1847 Walker and the 3 slightly later models of Dragoon pistols were intended to be carried in saddle holsters, and they wanted enough power to knock down a horse.
Anyone who has handled one of these guns (or it's replica) knows even John Wayne couldn't have carried one of these in a holster on his hip for more than 1/4 mile.
IMO by the time the Army choose a .44 in 1860, they wanted something smaller, lighter and easily carried in a hip holster even at the cost of some power.
After all, a man or horse who is put out of action is the prime idea with the military and a .44 pistol will do a fair job of that.
If you see one of these older Dixie Catalogs at a gun show or in a used book store, buy it! It has a lot of information that never changes. Just don't look at the guns they used to sell, and definitly don't look at the prices they once cost.
It's hard to read the tables when tears are in your eyes.