Big ++ on this one.
I know that if I am interviewing someone for a job and they don't have the skill per se but they have the temerity to have gone and looked it up enough to make cogent comparisons to their other skills, I will be at least impressed with their initiative.
Besides, one *rarely* gets a perfect candidate, so if no other candidate has Sybase experience, I would put the person who prepared ahead of the others.
Go for it! :-)