Oh yeah, those. I remember reading about them a long time ago. (Checks them in all the versions of FFIV I have)

FFIV for the GBA (both NA and PAL versions) and the US SNES FFIV don't have the hidden items while the Japanese SNES FFIV has them. I'd say those items are glitches if anything, since they were removed in later versions of FFIV. Yeah, it said that the PS version of FFIV has them, but I kind of doubt it since they're showing the patched Japanese SNES FFIV version in the screenshots that prove those items exist, rather than screenshots of the PS version. Also, I don't really think they'd reintroduce those hidden items in the PS version after removing them in the US SNES version. Then again, the PS NA version was based off of the Japanese SNES version, so it might have carried over. Either way, I'm certain it's a glitch.