...
You'd be surprised what can be done with storms. They can be made almost
invisible. Check with your local landmarks agency or not-for-profit. I'm
sure that they have a list of firms in your area that can make something
that looks acceptable to both you and the authorities.

Depends almost entirely on how anal the local controlling body is...some
are virtually impossible to get anything past...

If you can document the type of storm windows (if any) that were used
when the building was new, you might be ok. Failing that, glass or
plastic inserts that fit on the INSIDE accomplish much the same thing.