I sure hope so, because I was thinking of just that situation when I was planning my build... of course the level-gating on higher ranks of perks will do some of that limiting for me, but, yah, I'd like to hold a perk in reserve so that if I find a computer, I can put it in Hack... if I find a lock, I can put it in Locpick... if I find an NPC to talk to, I can put it into Lady Killer / Black Widow, etc...
I also hope (and expect) that we can look at the ENTIRE perk list ~whenever~ we want. As I recall, in previous games you only saw the entire perk list when you were at the level-up screen, and thankfully you could see ALL the perks, even those for which you did not yet qualify. Problem is, unless you write them down or something, it's easy to forget, like, how high does my STR have to be to get that perk I was looking at? And what level do I have to be?