Are these parts not pretty universal? Can another more recent model or even make bike's parts not work on my 34L?

Thanx, Cheers

Well the 34L arm is unique to that bike (ribs on the outside & snail adjustment on the inside) try finding a spare one when you bend one, sigh.

Whether Yamaha made guards fit all models over the years/models i don’t honestly know.

Mezo.