I'd say the more portable the typewriter is, the more likely you'll encounter bent typebars -- not least of which because an office standard typewriter may have been less likely to be treated as a toy (since kids wouldn't have been playing with them). But any typewriter in a flea market or vintage shop is subject to abuse, regardless of its original use.

Office standard machines may have more sturdily built typebars also, reflecting the heavier usage they would experience.

Bending (or in typewriter parlance,"forming") typebars isn't hard. Just go carefully -- a little forming is often all you need to get the slug to center in the type guide. Make sure you're only tweaking the portion with the slug itself, so use something like a small adjustable wrench to grasp the typebar right below the bend so as to immobilize it. You ought to be able to do the actual forming with your other hand, no need for another wrench to grasp the slug. But in any case, proceed carefully.

Can't help you with the d -- that sounds like the slug needs to be bent forward rather than side to side. But pictures will help. 

Good photos!  I assume the misshapen soldering job to the left with the two slugs side-by-side is the "d" and I'd say you are right on the money: that's not the way that machine left the factory and somebody did try their hand at a spot of soldering.  I've never resoldered a slug and I'd say that was ambitious for a first repair job and no, such things are not typical.  Whether or not you should try depends on your own confidence in your mechanical skills and resources.

It looks like the repaired slug is cold soldered - that is, using an inadequate heat source, which is why the solder looks like it was spread on like cake icing rather than nicely flowed. I would use a small torch but the issue is once the solder is melted the force holding the slug to the bar will go to zero, so how do you manipulate it and how do you align it? I'm guessing a special jig... like I say, up to your confidence in your own resourcefulness, or a repair shop...
 

I had a brainstorm about how to hold the slug in position - there may be enough play in the type bar so it could be clamped in the correct position even though the type bar will be bent. Then apply heat until the existing solder melts and we hope the type bar will relax to its rest position so all will be correct when it hardens. It might be necessary to make a coarse adjustment first so that the final adjustment can be applied with available play and without bending the linkage...

Just thinking out loud and maybe better to look for an experienced repair shop now so you would only have to listen to the commiseration about the former attempt and not experience the head shaking that you may have made it worse! You may have bought a lemon - a good looking typewriter which has some undisclosed mechanical defect that is difficult to repair.