You know, that box may predate the introduction of the higher pressure rounds. The high velocity may mean the lighter bullet.
I'm not 100% sure when Winchester was using that box design, but I think it was prior to about 1905.
I'm going to have to do a little more digging.
And, I would think that they would be lead bullets. Jacketed bullets were really just being introduced, and were primarily being used for the new smokeless powder cartridges. Jacketed bullets started to back fill into the old black powder cartridges later, I think.
As for the reloading statement, I think that was a pretty common position held by many of the manufacturers at this time. They wanted to sell loaded ammunition, not components.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.