Yes, just quote the model and the sailmaker will have the dimensions for quoting purposes. Once you get past the basic quote he may well ask for measurements depending on the type of sail you choose. There are many different varieties of sails, particularly furling mains so get several quotes and see what each one recommends. There may well be some contradictions amongst them as to what is "best" but you will soon get a feel for what the differences are.
If it helps I went through this exercise last year for my 33 as the original had gone all baggy. The r main choices are straight replacement but with better cloth, then one of the premium cloths such as Vectran and then with or without vertical battens. Kemps made mine out of Vectran (which is much more stable and long lasting than plain dacron) without battens but with spectra taped leech. Owain Peters at Kemps is worth talking to (currently sunning himself at Southampton boat show!)
