Metal plate you mention is most likely the shock absorber connection point that the bolt has to go thr. Try to push the schock body up or down to align the metal plate exactly right location to allow the bolt to go thru.
Here yuo can see the image of the metal plate on the shock absorber I mention above:
https://www.pelicanparts.com/More_Info/98633305131.htm?pn=986-333-051-31-M1012&SVSVSI=784&DID=5453
Also, place some anti seize paste (like copper paste etc.) on to the center section of the bolt, so it won't seize there again.