Slingerland copied Ludwig's crimped plastic head design too. Ludwig took them to court but lost that one too as it was decided that Ludwig's design was "prior art" meaning they weren't the first to use a similar design. There was certainly no love lost between the two crosstown rivals. Who came up with the new shell design (Slingerland 5 ply and Ludwig's 6 ply) first? Well, actually Gretsch did, but which of the Chicago titans was first? As far as the metal drums they are very cool but I'm not sure you could ever prove anything one way or the other short of some sort of factory paperwork or other definitive corroboration.
Did Gretsch really come up with it or was it Jasper wood products? I know that Keller sells drum shells as long tubes and were marketed for all kinds of things other than for use in drums such as for architectural elements and furniture so it is possible that Jasper did the same and Gretsch just decided to use Jasper as their source for cylinders of wood to make into drum shells. When Jasper went under, they went to the other manufacturer of wood cylinders. Rogers used Keller so they can't really take the credit either I suppose.
As far as the aluminum shell drum sets, there may never be a definitive piece of documentation proving either one's provenance. However, in the art world, unsigned art is often determined to be most likely from the hand of any given artist based on an overall evaluation of characteristics present in the unsigned work. Enough similarities to an artist's known style and quirks ends up with an assignment to that artist. This is usually good enough for the art to command the prices as if it it had been signed. Sometimes they are proven wrong though...
As I have stated earlier, the construction of the gold kit is exactly the same as the early grained finish Slingerland and Leedy badged drums. Not just close. Exact. The aluminum Ludwig kit exhibits the same construction that they used on their first gen and "prototype" Acrolites. Those would be check marks toward having been made by these two companies.
As to when these were made, that is up in the air for sure. The more I look at the Ludwigs, I notice that all of the hardware is later than early 60s. The tom mounts have the larger thread on the eye bolts, it has the large cup washers for the lugs and has a chrome diamond plate on the bass drum and plastic handled curved spur brackets. These could have all be changed at some point or it could also be that they were made much later. Perhaps as prototypes when Ludwig was considering metal for drum shells that would eventually lead to the stainless steel drums. They already had a formula for construction so they could have had them made up as a test and ultimately ended up going with Stainless. The construction method would be much cheaper than having shells spun or rolled and seam welded with angled bent edges. Who knows, they might have made a stainless kit with the same construction method. No telling at this point, but discovering the source of unknown objects always starts with "conjecture and guesstimates", or a better term would be varying hypotheses.