franc

Hi guys and gals, I am dropping a line to introduce myself, and ask for help. I have come into ownership of a Montesa Cota, (well most of it). I am interested in taking up vintage trials events in my local area,(Wye valley area) and I'm in need of info and parts, I believe I have a Montesa Cota 200/175 frame and engine numbers begin 29M, I have been told this is an 86 model???? I am missing seat/tank unit, and in need of a gasket set. Do other models of seat/tank unit fit? Are the gasket sets of the 124-247 units universal? If not can anyone point me in the direction of where I may be able to obtain these parts? Cheers Franc.