If I ever saw the sequels to the first Planet of the Apes... I do not remember them, if I did.
Just checked ono IMDB.... yeah, they made a few back in the 70's, (the original came out in '68). I didn't count so I don't know how many... a couple at least... and I read the synapsis and no, I'm 99% sure I didn't see any after the original. Worth it? I remember enjoying the original.
Sidenote: Universal used to have the props used in Planet of the Apes spread all over the entire lot, quite visible on the tour. Thru the years it was sad to visit and see them slowly deteriorating. I doubt if any of them are left now.... but back then they were everywhere.
I like your hobby of collecting movie props.... care to make a list of them? That kind of things is very interesting to me.... I don't collect, myself... but I think it's something I might like to do going forward. - JamesJM