In my experience, all manufacturers fitting 1RS bearings fitted them with the exposed side to the inside of the hub. Water gets past the dust seals, down the spindle and gets held inside the hub. Bearings rust from inside.

Never came across one fitted the other way from the factory.

You are of course right about the clearance.  Had a brain fart.  Considered the interference fit of the outer bearing race and not brought the loose fit of the spindle into the equation.
 

Tinkicker- I see you've deleted your post defending C3 clearance on a wheel bearing.  I will edit my response below to show that Yamaha did not spec C3 wheel bearings on at least some models...  (I believe normal clearance was specified on all Yamaha Enduro wheel bearings, I don't have the time and energy to "prove it"...  but feel free to post any specs you might find.)

...........................Speaking specifically of Yamaha, their early parts books and listings often showed the generic part information if applicable...  for example they would list the industry standard bearing number.  

Here is the parts book entry for a CT1 crank bearing. Clearly shows a C3 clearance spec: 


From the same parts book, here are the entries for the rear wheel bearings, no special clearance shown. 
 



 

Tinkicker, I see you snuck in again with another post while I was editing mine... 

All good! 

I have opposite experience...  for one, some early bikes came with "1Z" (normally designated "Z") single shielded bearings instead of 1RS single seal bearings.

I also distinctly remember thinking it was silly that they put the single shield/seal towards the inside of the hub...  I was just a kid then and a mechanic at my Dad's shop put the whole wheel into the solvent tank, turned on the pump, gave me a brush, and instructions to wash all the old grease out of the bearings.  I took a solvent bath by the time I was done!  Really dried out my skin, "real" mechanics didn't use gloves back then.  Then he showed me how to repack them. 

I really can't remember if it was just THAT wheel that had the unshielded side out?  Because what you say makes sense, and it made sense to me even then.  Frankly for the past 20 years or so I just knock the bearings out and replace with 2RS versions.  All balls used to have inexpensive kits (less than $10 shipped) with Koyo 2RS bearings and new seals...  or a bearing supply house had them.  Wasn't worth trying to repack and reuse old wheel bearings. 

It is very possible that bike had the bearings "backwards" and that is a pretty vivid memory so it's what I remember.