The F-spaced or TB-spaced thing only applies to the bridge pickup, the neck will always be ordinary bucker spaced.
And yes, if yours is an Ibanez RG, especially if it's one with a trem (most probably an Edge) then it will most definitely need a TB-spaced bucker in the bridge.
In any case, having the E strings be on the outside of the poles is a dead giveaway.
However, although several people, myself included, will attest that they can clearly hear a difference, it has more to do with the balance in volume between the strings that do line up correctly and the ones that don't, especially when bending strings.
It rarely has an appreciable effect on the tone of the pickup.
Adjusting the pole pieces however, along with pickup height IMO makes a HUGE difference.
It happened to me more than once where a pickup sounded bland and/or wrong in a guitar and then turned out that all that it needed was a simple adjustment in height (both the pickup itself as well as individual adjustment of its' screw poles).
Made all the difference in the world.
I tell you, if people actually tried that there'd be a lot less returns...