Hi. The first good set of drums I ever played in my life was my friend's ruby strata 5-piece. I had been playing a Tempro set and then when I got to play the real thing, I was blown away.
The Standards were Ludwig's answer to compete with the lower priced import drums. The lugs used on the Standards were also used again on the later Rocker series of drums. As you know from looking at them, they were round-ish and easier to polish -less time -less labor-intensive and yet completely functional.
The shells, edge profiles, rims, throwoffs, etc. were exactly the same as anything on the Classic line. The tom mounts were slightly different, the lugs and the finishes were the unique aspects that separated the Standards from the Classics.
I suspect that the reason they painted the Standard shells was that they might have been shells that had a blemish (like knot or something) on the interior-ply and they used the paint to cover up the imperfections...that's my guess, anyway.
The hi-hat pedal and bass drum pedal were reeeeeeaally simple mechanisms and I don't think they held up very well over time...but I thought they had a cool look and I especially liked the Standard cymbal stands.
I still see a few Standard kits and/or parts come up on Ebay. They aren't "sleepers" anymore, though! They are commanding top-dollar if they are in good shape -especially a Strata finish.
As far as stamnped dates in the drums... I have drums that have them (white-painted interior Classic) and I have them where they aren't stamped (clear-maple interior Classic).
I know that some Standards were stamped, too. People used to wipe those stamps off sometimes, though.