Not quite - remember, once told where to go, the servo will go there at its own pace, so you can only slow it it down (and you cannot speed it up) by telling it to move smaller amounts or longer periods of time.
There are at least two ways of looking at the problem:
1)Break the move into, say 1 "degree" steps, and work out how long (in milliseconds) each step lasts
2)Break the move into, say, 1/10th second steps, and figure out how big (in fractional "degrees") each step is.