Interesting info and I like your thought process Jack. I also like you, from what little I actually know of you and I have a respect for you and your service to this country. However you have stated here on more than one occasion that you are not a true Randall collector as much as an accumulator. I'm paraphrasing but think I'm close. You admitted not to being a Randall expert. Well neither am I but I have been studying, collecting, investigating, holding, touching, and asking a lot of questions since 1980 about every aspect of Randall Knives and all things Randall....including sheaths.
That said I will point out the difference for you between a JRB and a Heiser. You noted Sheldon's work and I have his book. Sheldon did a great job being a newcomer to Randall's not too many years before he wrote his book. He, like many of us fell head over heals for these knives and their history. He research his book well and it has a lot of useful info. However it is not without flaws. I'm not knocking his book as I keep his book close as I use it regularly.
Mr. Randall always sent a sheath to whomever was about to make a sheath. I think the Stockman deal is interesting and good work on Sheldon's behalf. But the bottom line is this. The sheath that is with the Astro on ebay was made by old man Johnson and there is a simple way to tell. The sheath with Grissom's knife in that State Park Museum was made by old man Johnson. Not by Heiser and not by Stockman. Maybe Stockman made some...maybe a few...maybe one or two. I don't know.
You read where Stockman allegedly took a Heiser apart and used it as a template for making his sheaths. So did everyone who made sheaths for Randall knives.
If you look at the heiser you show above from Sheldon's book notice the point at the bottom of the sheath. This is a trait on just about every Heiser Mod C sheaths that I have ever seen. The point is clearly obvious. Notice the sheath with the Astro on ebay. It has a more graceful rounding of the point. (I don't know if I'm explaining this right) notice too the lack of this point on Grissom's sheath. I have never, ever, never, ever never, never never....witnessed this clearly defined point on a Johnson. I have seen a few Johnson sheaths that were not buffed or sanded as much as others and one might think there is a point but I don't believe it to be intentional as much as just not finished off as well. If you have or have seen a Mod C sheath built by Sullivans you will notice that for what ever reason they have decided to go with the point. Personally I like the gentle graceful curves of the Johnsons. Robert Hunt mentions this exact graceful curved sheath of Johnsons in one of his books. My comments here may sound crazy or stupid but look at the sheaths....hold many of them...look at the stiching and soon you will be able to tell the subtle differences between the several sheath makers thru the years. I also believe...and could be just as dead wrong as possible, that some sheath makers have used different quality leathers. Just an opinion of mine.
At any rate Jack don't take anything that I've said here and go bet the farm on it. Like I said I'm no expert. After all what is an expert? An EX is a has been and a SPURT is a drip under pressure.
Sorry this BS took so long.