I remember when I rode Beta's on a couple of guided trips in Andalucia and the guide Trev used to say he didnt think the plastics wern't quite up to KTM standards. I guess you are finding that that is the case
I dont think a plastics kit is too much money for a refurb at some point.
Glad the bike seems mechanically up to scratch.
Oh, and I 'polished' off the anodising a bit when my rain jacket came off the back and wound itself in the sprocket, dragging the chain guard against the wheel