Mine is an 86 not an 87, but I did consult my boats order page and it stated that the fiberglass platform was STD and the teak was $95 extra.
As far as getting a teak platform, if your looking for OEM you would have to find someone with a boat they are parting out (thats what I found) or you could make one or have one made. Some have taken them off of other boats (i.e. M.C.'s or Tique's) and either cut them down or cut them at a radius to fit. A few here have made new platforms from scratch and made their own patterns, not OEM, which I think is pretty cool as well and shows off your creativity.
According to a post I remember Ron commenting on, to have one made now bye him...... the cost of a glass or teak platform would almost be the same. I cant find it, but he may post up here.
