Top of my head, but I think it's only colour options that changed with Mk1 screens (bronze, or bronze with blue top tint?). I'm pretty sure there's a difference between mk1 and mk2 screens, but I can't remember what it is. It's very slight though, maybe just the shape of the bottom corners?

You don't always need new trims, however most have had new screens one time or another, and the trims are often glued in with overspill, so invariably tear when being removed for screen replacement. So it'd be best to get a new inner and outer if possible