It depends - the fitters out at Oceanside can tell you within 200 spin and 1/2-1° of launch just by sight because they have seen so many. If you are having a good give and take conversation about what launch you want to see and the ball is going straight and rolling out sufficiently, you should be okay. Where it will make a bigger difference is comparing shafts. Sometimes, the best feeling shafts aren't always the best launching and spinning shafts for your swing and a launch monitor can help.
Cathi @TeamTitleist 1-888-TITLEIST
Yes, you need trackman to properly do a fitting along with the other tools..IMHO