Are the ears on the frame brackets centered on the base? I can't tell from the pics. If not, is 1 brkt on the frame up side down? If that's not the case, it could be that the x member has collapsed inward.
There are measurements for checking that dimension. AIRC, it is from upper a arm mount to the opposite side.
A frame shop should be able to check it.
Does it have offset upper a arm cross shafts in it? If so, that could be an indicator of frame sag.
I may have a frame drawing. I'll send it to you, if you will send me your email addy.