Take a look at this picture of a Ten engine, transmission case, and final drives.  What all do you see that is different in the picture than what is on production machines? 
 

Ken, you are definitely the guy who knows and or finds every detail or change in these old machines!

I see several things in this picture. At least ten things are different. They used that picture in their sales book for the Ten and the Fifteen .
In my line of business; Artists don't capture every detail we machinists and mechanics see. I deal with things similar to this every day.
Want me to name a few?

I see about ten, depending on how I count. There is a bit of early L Twenty carryover in the trani area. I love looking at these old pictures for changes.

That would have been a better drawbar. Skinner

I was wondering if that drawbar would have been better or not. I have seen a few L/PL Twenties with that style of drawbar that had broken castings, bad swing plates, loose bolts etc. I will freely admit that the drawbar used on the production Tens and Fifteens is not ideal in any way. I would bet that the bean counters were involved in the discussion

Longer draw bar in swing position is better for turning pulling an implement.
Here's what I'm seeing in picture. If anybody cares.
1. Radiator tank slightly rounder on top
2. Fan shroud
3. Exhaust manifold too tall in heatbox area and missing pipe plug to divert pipe down.
4. Spark plug wire pipe has one big radius
5. Priming cups
6. Oil cup for throw out bearing is drawn where the oil fill plug is
7. Wrong number of bolts on steering clutch adjusting cover
8. Clutch and Brake pedals
6. Valve covers
7. Flat tabs on top of engine bell housing
8. Sprocket missing bolt holes for pulling them
9. Final drive bull gear cover doesn't look correct
10. Transmission filler plug on bevel gear cover
11. Drawbar
12. 23 teeth drawn on the sprocket. Should be 25

You found a few that I did not see. I did not count the sprocket teeth, and I was too busy looking at the front of the spark plug wire pipe, trying to decide if it was too long or not and did not look at the back side of it. Missed the sprocket bolt holes, I looked at the flat top of the bell housing but rationalized my way out of that one, and should have kept it on my list.
A couple of other things I found
1. the mag drive shaft bearing has two bolts.
2. The magneto mounting plate is mounted to the engine differently
3. Early Twenty steering clutch greasers on the rear of the trani case.
4. I have also been looking at the radiator overflow tube, thinking it comes out lower in this picture, but I have not looked at the back of a Ten radiator tank in a while.
I was just looking at the picture of the trani case in the parts book I have, Form 4863 and the trani case on page 47 has no oil filler on top. On the trani case and drawbar you can see where the engineers were using things that they had done on the Twenty, only to change them when production rolled around.