it usually depends on the combination of MSI and MST,
the only way to find out is to test it.
for a quick test you could open it with orca (or whatever tool you used to create it).
if the new MSI it too different from the old one, a warning or error will be displayed.
for the definitive test you need to install it.
if your MST just adds rows its never a problem.
lets say you create an MST that sets REBOOT in the property table to "ReallySuppress",
you could apply this to any MSI without problems.
of course you need to make sure the changes still make sense in the context of a relational database.
if you modify or delete from the original database you need to make sure the new database still contain the same rows you address