You can use the old type focussing screen with the exposure meter on the H/B 500CM. But as stated, the new type Acute Matte Screens, produced since 1998, are brighter. Hasselblad say, they give a more accurate reading. You will not need to remove the screen for any purpose save to clear it of dust, it is only a matter of sliding a clip each side of the screen to remove it.
I have both screens for my 500CM (C. 1980), they work perfectly well with the meter eye level focussing hood with the old or new screens.
It may well be that the very latest hoods are calibrated for the latest acute-matte screens only.
It is also worth bearing in mind that Hasselblad have produced eight different screens, and four different focussing hoods with meters since 1970. As far as I am aware all will fit the 500CM, with meter or not.
I think you should ask yourself whether you really want the meter version as I have found it less useful than a good quality separate meter that can be use for refective and incident reading with spot preferences.
However, they state that the acute-matte screen is the only screen that will give correct exposures with the latest Meter Prism Viewfinders.
Get in touch if you need more help. Stan. L-B