Marzocchi slider grooves

[skiracer]

So, in working on a set of 35mm offset axle Marzocchi forks, I took the C-clip off the bottom of the slider to allow the damping rod to come out.  Afterwards, I noticed there is another groove on the inside of the slider about 1.7" further in the tube from the bottom groove.  I don't have anything to measure that deep into the tube, but, it looks like the same size as the groove on the bottom that the C-clip fits into.  My question is, what is the second groove for?  Is it there so that the slider can be cut and shortened?  Anyone?

1976 250 MC5 Original Owner
1976 Penton 175 XC