No, just use a relatively fine tooth (triple chip) TCT blade raised 1/2in or so above the plastic and keep things moving briskly (2 or 3in / second).
(The following is from my training notes when I have people in the shop) The biggest enemy when machining acrylics is heat build-up, so watch the cutting point - if the plastic becomes gummy and sticks to the blade you're feeding too slowly. Feed too fast and the acrylic may chip or craze. Watch for the tendency of the saw to grab the material and wear a mask as cutting acrylics releases plasticisers which can cause a headache or nausea with prolonged exposure.
I normally use the tablesaw for rough cutting then finish on a static router to get a better quality edge (again using the largest size of cutter to improve heat dissipation), but watch out because once cut acrylic can have knife-sharp edges, so remove the arisses (sharp edges) with a fine file before using your jigs. Don't worry about the edges looking "milky" the only way round this is to flame them - a process which requires a fine jet, high temperature acetylene or hydrogen burner. If you need to drill, use a low speed (200 to 300 rpm). Acrylics tap well, but use wax to lubricate the taps and choose a coarse thread as fine threads pull out too easily.
Sorry to bat on, but I do machine plastics as a sort of side line...
couple of thoughts...
whichever method you use, leave the backing plastic on the perspex until the job's finished. It not only helps prevent scratches, it lessens the danger of the stuff fracturing on you too. Historically I back up the protection along the cut with layers of masking tape too.
As for cutting, it may be simpler (if the shape is pretty basic) to cut it by hand; using a sharp knife and straight edge, score a line along one face (similar to cutting glass). Pay particular attention to each end of the cut. Once scored, hold the piece over the edge of the bench, score aligned with the edge, scored side up. Simply bending the material will propogate a crack along the score line. Deburr the edges with a file, but be carefull, they're razor sharp.
I work with the stuff all the time, making covers etc.
Acrylics come in lots of different thicknesses and colours (Perspex was ICIs trade name for it until they sold out a couple of years back). For anyone interseted your local signmaker will probably give you offcuts or scrapped signs in 4 to 6 mm thick stock for making templates. Best thing is it's free.