Restricting opening the menu would not be secure as it is client side and hackers would be able to open the menu regardless.
But you can restrict all models for users by changing server.lua
if not restricted or IsPlayerAceAllowed(src, "pedmenu." .. model) then
to
if IsPlayerAceAllowed(src, "pedmenu") and (not restricted or IsPlayerAceAllowed(src, "pedmenu." .. model)) then
And now to be able to use any ped, players need the “pedmenu” ace. You can then give admins access to models with
add_ace group.admin pedmenu allow
And you can still restrict individual peds for individual admins as normal.