Every once in a while I get a light for a gift (and one for myself of course) or I double up on an order because a friend wants me to get them a light. When I receive them I do a side by side comparison and keep the one I deem as the best. I just did that with a Fenix P1 that I got for my brother and myself. There is no special reason that I got my brother the light other than he is into gadgets. I will send a light back if there is something wrong with it but I keep the best tints and smoothest switches for myself. I also deal with warranty issues for the people I get lights for.
I guess I'm feeling a little guilty today...
first off, getting a gift for someone is a very kind thing to do. so, try not to be too hard on yourself. the person receiving the gift should be grateful for either of the two lights you give. after all, what did they do to earn it? if they earned it, then it ceases to be a gift and becomes a wage, does it not?!!
probing a bit deeper...
as with many (not all) decisions we make and actions that we take, it's the MOTIVES that are often more important (not speaking of misguided motives here; there are times when people are both sincere in their motives AND are still "sincerely wrong"!).
so, ask yourself, what is your motive/motivation for doing so, and is this why you felt "a little guilty"? in other words, WHY did you do what you did? only you can answer this question for yourself. your answer will determine whether what you did was right or wrong. it may be right for one person, but wrong for another - in a matter like this, it will all come down to motive, IMO.