I have laid my eyes on both solid lifter cams and hydraulic lifter cams from 235s, and I cannot discern any difference with my eyeballs.
It is very easy for me to recognize a hydraulic cam from say, a 350 by looking at it. The profile of the lobes are substantially different, and stand out like a sore thumb.
What's up with that?

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission