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I'm don't think it would, but thats just a guess. I think the FE1 is thicker due to the way the spring is wrapped. Doesn't look like it's flat bottom. The FE1 insulator has to rise up to support the spring for 1 wrap.
Base spring
For example, below is a Z51 shock with a Z06 lower insulator (left shock) which is flat. You can also see the Z06 springs with the flat bases.
