Just had one off GRP scooter products. The early px type. Needed minimal fitting. Tried metal ones but all seem a mile off and it's a lot easier to trim a fibreglass one
Think it’s the luck of the draw with some of the toolboxes also dependant on shape of thenLegshields I've used both series 2 /3 and GP type of Martin at just lambretta and Warren at shawfire all needed some type of fettling I’m afraid but not too bad
I got one for the 150S at a rally from a couple, think they were from Wales, and it fitted almost straight on but the one for the S2 lost a lot of metal.