I did not know that.
My 97 is an early build, and both my 96 and 97 have the round cannisters with the storage box--which have become a place for my relay-fuse box.
Edited to add: Now that I think of it I replaced the inner fenders on my 96 with a 97 or 98 Suburban inner fenders. They were identical to my originals and everything bolted right back on.
I got to learn a lot about how the box is installed, by removing 7 or 8 in the LKQ pick a part back in February. It took that many trucks to get 2 good boxes and 2 good lids. The hinges get broken on the lids, which makes it difficult to find a complete assembly in good condition. The one I kept to put on the Burb is a box from one truck and a lid from another. I'm not doing a restoration so it doesn't matter to me!
The rectangular vapor canister bracket has tabs on it that interlock with the flat end of the box. The other end h as a protrusion that goes into the inside of the fender, where the screw goes into a speed nut that should already be there.( my Burb has it.) Then the stud on the bottom goes through a hole that has to be drilled, if it's not there. But the inner fender panel has a raised boss where this hole will be, so you just need to mark it and drill. I'm going to put paint on the end of the stud and set the box in place; this should mark where the hole should be made. I'll probably make it a little bigger so there's adjustment room. Once it's installed, it won't go anywhere.
Just haven't done it cause I need to replace the washer bottle and pump. I want to grab one at the yard, since the GM ones are made heavier than the aftermarket ones. Also if it still has juice in it, then it doesn't leak!
Anytime it's not raining here and I have money, it's just been raining so the place is a mud pit.