ID for KZ fuel tanks in junkyard?

I came across these KZ tanks at Bob's motorcycle salvage in Phoenix while looking for a rear brake pedal for the 9. I had to do some climbing up on the racks to get them all in one place, but as it's one of those "Go out back and look kind of places" no one stopped me.

I was looking at the tank on my 1976 900 LTD and it's smaller than the non LTD KZ models. My tank has the round threaded bung the petcock screws onto. The larger tanks in these pictures have the slotted fuel opening for 2 threaded bolts to hold the different style petcock.
These caught my attention because I was contemplating getting a larger tank for longer trips. Does anyone here know if the LTD came with the smaller tank, or did some prior owner put a smaller tank on my bike? If I'd had a Sharpee marker I would have numbered them but I wasn't expecting to find all this.

I think the LTD/CSR always had a smaller tank than other models.

Is that yard north of Phoenix near the foothills?

South Phoenix on Elwood Ave. Literally a thousand of bikes of all makes in the yard and piles and shelves stacked to the ceiling with boxes and boxes of loose parts. Lots of the smaller KZ's 650 and below, but the big bike parts are gone for the most part. I did find a Kerker header for my son's 81 KZ 750 for $80.00

The KZ 900/1000's had larger tanks like the Z1's.
Steve