I wouldn't say it has no bearing. If C. elegans could NOT be uploaded in a way that preserved behaviors/memories, you would assign a high probability to human brains not being able to be uploaded. So:

If (C. elegans) & ~(Uploading) goes up, then (Human) & ~(Uploading) goes WAY up.

Of course, this commits us to the converse. And since the converse is what happened we would say that it does raise the Human&Uploadable probabilities. Maybe not by MUCH. You rightly point out the dissimilarities that would make it a relatively small increase. But it certainly has some bearing, and in the absense of better evidence it is at least encouraging.