It's always interesting to see what people have done to these old bikes over the decades. Sometimes it's necessity. Sometimes it's just preference. I think Mikaw is correct. The gauges are probably '76. The tach for sure isn't from a Z1. The dash is definitely Z1A or B. (lettering is under the light)
The rake and trail are the same for a Z1 and a KZ 900 so the triple trees are interchangeable, but the mounting holes for the dash may be different.
I have a couple of Z1B's restored, an '80 KZ1000LTD restored, a 1981 KZ550 restored and a 2008 KLR 650 for off road fun. My wife has a 2019 Suzuki DR 650 for on and off road.