Military Watches: Issued or Non-Issued.

Are there any case back markings - need to see the case back. It might be one of the many military used (not issued) pieces bought individually due to their multiscale chronograph layout with a telemeter scale, I guess used to estimate distance to an event such as artillery fire, explosions, or lightning by timing the delay between sight and sound.

Where did the idea of it being a "Uruguayan military order in the 1940s" come from?

Of course, Uruguay did have established armed forces throughout the 1940s (both army and navy). Uruguay broke relations with the Axis powers in 1942 and declared war on Germany and Japan in 1945, but I think they just wanted in on the United Nations.

Regarding your Vulcain, it's plausible that a Uruguayan military officer could have owned a Swiss chronograph in the 1930s–1940s. Swiss watches were widely imported into South America duroing the late 1930s. To prove that your specific watch was issued to the UM you would need evidence such as:
1. Military engravings on the case-back,
2. Unit markings,
3. Inventory/property numbers,
4. Or documentation linking the watch to a military contract.

Our military watch collecting hobby is full of wishful thinking 😉 I have the "could've been" watches to prove it too. 😁

I am curious as to the case back. I have never seen the lone inscribed D without the trailing H, but I know they definitely exist - super rare I suspect. I think I read somewhere once that only the Wehrmacht officers' watches had the D xxxxxx H inscriptions and general service had D only? Perhaps someone more knowledgeable could chime in. The DH of course stands for Dienst Heers (Dienst Armbanduhren des Heers). Any backstory on it?

is the movement serial a bit on the high side?

The type 2 is just epic! Precista are in another paygrade these days - the last 1982 Precista I saw sold was USD12.5k. and of course the FAPD is another classic. Great group of mil watches. That precista has been roughly scratched and I think for the exact reason you suggested.