I'm not saying don't ride it.
I'm not even saying it's worthless.
I'm just saying that there is no reason to ever buy a suspension fork with a non-tapered steer tube and a 10mm quick release for an obsolete frameset. You are throwing money at nothing, because handling stiffness is more important than suspension travel for the sorts of stuff you will ride with a bike like that. It's more important to be able to put down a clean line that it is to soak clean hits with a full-rigid. If the full-rigid in question can't accept a suspension fork that will still retain adequate handling stiffness, then it is a downgrade rather than an upgrade.