I know it's an old thread, but I'm new here, found this in a search, and may be able to answer a question that came up in this thread about the M1941 Johnson.
I bought one six months ago, and had educate myself on them in a hurry!
The reason for the area of funny looking wood is because the stock had that area laminated on. They call these areas the stock "cheeks". The Johnson's buttstock swelled to a little over 2.5" wide at the rotary magazine housing to give it some protection. A standard stock blank of the time was 2" wide and fine for most rifles, but not wide enough for a Johnson. The solution would be a wider stock blank, but since there was a war on and everything gun-related was hard or impossible to get, Melvin Johnson was lucky to get standard blanks. So he had a piece laminated onto each side and milled the stock to shape.
So if the wood pieces matched there, it was only by accident and it usually didn't, so stuck out like a sore thumb.
Add in typical damage from handling, and it only made the laminated area more apparent. Most are pretty dinged up there. It would be hard to avoid banging it into things.
The "cheeks" of the one shown in the pictures sure isn't one of the better looking ones as far as this area goes!
I also notice the rear sight has been modified to a V-notch on the pictured rifle. This is fairly common too.
The original sight is a peep. It is a square shape with a very small aperture in it. Marines did this notching at the time, and it was also done in "sporterizing" attempts after the war.
I'd rarely take a V-notch over a peep but after owning and shooting one a little while, I suppose I can see why they did it. That aperture is tiny. It is OK on the range, but would be a bear to use up close and fast.
It looks like this:
It does appear that the Johnson SAR was the first semiauto to see use in WWII- even before The M1. Some Marines had them in the Guadalcanal and Bougainville fights. The USMC never officially adopted the Johnson SAR (they did use the Johnson LMG in the early Parachute Regiments) but had some around. They never ordered them directly from Johnson Automatics, but instead had part of the Dutch delivery diverted after the fall of the Dutch East Indies. Best estimates put the USMC as having around 750 Johnson SARs.
Which brings up the Garand vs Johnson thing.
I've read things in the past few years that made it sound like there was a big face-off between the Johnson and Garand rifles. Based on what I have read lately, this was mostly the work of reporters, gun writers, and a couple of senators, and I don't think it ever did amount to much.
A lot of people in the USMC wanted the Johnson, but since the USMC was a "customer" of the Army, they adopted what the Army adopted. Although some pushed for USMC adoption of the Johnson, there is little evidence to show that Melvin Johnson expected this. He did want to have a rifle ready to be submitted as substitute standard in case the Garand didn't work out or production couldn't be met.
After having shot both (I am a Garand nut) I can't say that I favor one over the other. I can name a few things I like better about one than the other, and do it for each one.
I don't think the outcome of the war would have been any different because one was issued over the other.