“Interesting that the reservoir for the rear shock absorber on your model is behind the spring, whereas on the other models it is in front.”

It scares me that I never noticed that, and mine sits right next to the other models!

The discussion about the thermal flow being forward or rearward has me wondering if they function properly if inverted top to bottom....  I don't understand how they function. 

I would be interested in flipping my rear shocks on my 2017 SCR950 if they would still function properly. Flipping them would give me the look of our mid 70s model enduros. 

imgur.com/a/SZzvm71

Your modern reservoir shocks are gas charged (likely with an internal bladder or piston to keep the oil separated from the nitrogen) or they could not be mounted "body up".  Advantage to mounting the body "up" is less unsprung weight, but gas shocks can be mounted body down...  the shock itself will not know the difference.

(The original Thermal Flows were not gas charged and should never be mounted body up)

So if the mounting and clearance allows, you could flip your SCR950 shocks "body down".  On such a large heavy bike, I seriously doubt you'd notice any difference with reservoirs and body "down" if you like that look better.

Looking for confirmation.

It also effects the exhaust. The DT175 A & B exhausts don't quite fit the 1976 DT175, the different frame geometry means the under seat mount is just a few centimetres nearer the exhaust port.

The 1976 exhaust mounting bolt hole is slightly further along the exhaust.

I have never directly compared the exhaust to see the exact differences, but 1976 DT175 US model exhaust is definitely different compared to 74 and 75.  

Fuel tank on 1976 DT175 is a different size, shape, and mounting dimensions compared to 74/75 as is the seat.  

There are differences in internal engine parts too...  1976 DT175 was a "transition year" to a smaller diameter transmission input shaft so some of the clutch and trans parts are also "one year only" for the USA market... 

Other countries had "twin shock" 175 options beyond the 1976 model year so it's very likely that outside the US you will find some or all of the US 1976 twin shock DT175 updates maybe into the 1980's or however long they offered twin shock 175 models in that area of the world.

Bit of trivia is US market did not get a 1977 DT175 (or DT125) model.  For the 1978 model year, Yamaha introduced the monoshock DT175 (and DT125) in the USA exclusively.  No more twin shock 175 (or 125) after 1976 here.  

Thanks very interesting MarkT, good to note if buying parts.