I agree, better safe than sorry. I think that the chances of them getting a better home are pretty good so I wouldnt worry. I once had to do this with a common pleco as soon as I found out how big it was going to get and for months it was at the LFS but then I found out it went to a 200 gallon tank in the same condo complex that I lived in then! I actually visited him once!
Good luck with your tank in the future. It is good to see someone who cares enough to do something like you did. I often wonder why it isn't advised more often to just trade a fish back in when that can, at times, be the more ethical solution.