I attach some images of one of the joints in the lower part of the frame on my RT2 which I am about to send for powder coating. The right hand joint appears to be partially open whereas the left side is not. Is the appearance of the right side normal? Should I be looking to get this welded prior to powder coating? 
I can see no evidence of other frame damage, no twist or torsion or evidence of a crash.
Left (normal) side  
Right side
Right side
 

Right side is a concern. Left side is a product of mass production tolerances.

Left side looks ok to me, but you think the right side is a failure of the weld?

It looks like very poor welding from the factory.  The japanese manufacturers were notorious for poor quality welding back in the 70s and 80s.  Yours happens to be the worst I have seen.
 

Agreed, little touch up on that right side,. Tinkicker is right, some of the 70's frame welds needed touched up when new , had a similar issue with my RTMX where the weld did not penetrate 

Thanks Guys. I'll get it checked out at the welder's tomorrow.

I just checked my 73 Rt360 that im doing and it looks better than yours. id touch up those welds if i was you.