My wife and I are staying inside...except for the grocery store. We are doing OK so far...hope you and yours are, too. The internet really comes in handy under the current circumstances.
There is a little challenge with the rear "caps"...they are alloy ('pot metal') as you mention; but since there is no stress between the caps and the fender sheet metal, mine have 'held up' very well. Can't tell you how the seams were filled in (about 12 years now), but I get a feeling it did not involve any heat/metallic filler...maybe Sluggo knows.
The front seams - connecting the upper apron with the front fenders - are a different matter (see the photo). There definitely is stress at those joints, but the pieces are (of course) bolted together and then welded. I was told if I had to jack up the front end, to do so by placing the floor jack under the coil spring(s) rather than the side (frame) of the car. There is a very slight "wave" on the passenger side, but you won't see it in the photo.
I apologize for 'ranting on'...hope I helped a little.