I think the case color varies greatly from gun to gun. The "straw color" comment I agree with as I see that color more abudant in later guns too, but I have no idea why.

I spoke to a fellow collector whom has SEVERAL .410 Elsie's...he relayed a story to me on how it was found that there were several .410 barrels found stored at the factory. They didn't want these to go to waste so they "pushed" a group of .410's out at the very last bit of production.