Well for the front spring pivot point, non shackle side, it looks like youd be fine if you just cleaned up the metal and then welded the adapter on.
on the rear, i honestly couldnt give you an opinion because its hard to tell whats going on.
it looks to me like the po outboarded the leafs to match the perch width of the toy axles..
this could be good or bad, it could be a potential breaking point. Maybe gusset the crap out of it, lol.

 

Ya, a good 3/8" thick gusset from the outboarded rear hanger to the frame would make it notably stronger. But 2 gussets (middle and front) to the frame of 1/4" or heavier would make pretty bomb proof.

Hope it's working good for you!