There are NO, Toneaus for the 1980-1993 Mondials [ http://www.ferrarilife.com/forums/showthread.php?t=8760
First, I believe you would not be able to mfgr a decent toneau for to waterproof the controls or seating area and that is more concern than the top [manually-mechanical not hydro/electrical] mechanism, which is always
protected up or down. The outer top cover always covers the more general areas.
The Mondial 500, I believe had a side cover for that passenger area, but not sure.
There is a shipping cover of sort, to protect the roof and sides, but is not a driving piece of equipment: Storage or shipping only.
The normal soft top for the cabriolet. Driving up/down makes no difference unless weather is a factor. The front rubber piece where the top meets the windshield WILL go hard and less compliant over time, about 10-20 years if left outside, but I store mine inside and it has lasted about 20 years. Needs replacement now and about IIRC $300+ or so.
The ONLY damage I can imagine is either stains to the top [up or down], creases to the top in down position, or UV damage or scratches to the rear window. BTW, that top is so tight, that 'creases' go well away. IMO it is a very good looking top vs other more moder soft-top models.
Although my top looks like new, one should quickly clean dirt, which accumulates more inside than out: Don't know why, but that top is easy to maintain IMO. Very soft/light soap with white rag, clean quickly and it'll be good to go.
Some cabrios, had a sort of Sun roof, where the same applies in regards to weathering/damage to rubber bits.
I live in CA so weather is more mild, but I DO drive in the fog, with top down sometimes and heater blowing. I drive a LOT with top down in 90F+ weather for over two hours each way at a time, and A/C blasting and not a problem [freeway speeds of about 80MPH helps]
Many put a small soft, now microfiber, cloth over the window area just before top down---I've gotten lazy, and feel I'll just replace the window someday as after 20 years, it is looking a bit hazy but not bad. Fortunately I only look through it when it rains, and all I see is headlights in my rear view
IF you are saying the tops leather protector
then it serves two purposes IMO:
1. Dress up, which is very nice
2. Keeps the nasties out of the hard to clean areas
that's it. I've seen many not use it and can only think they are either missing it or don't understand how to put it on correctly or one of the pins/connectors is broken
Tops sell on ebay for not too bad a price with correct snaps, but 'cheap' so: RICAMBI will hep there...you'll like what you get, get it right. Couple of Mondial owners from RICAMBI
the snaps are easy to get as used on many
euro vehicles: RICAMBI sponsor here has the Tenax clips.
the top is VERY tight and challenging but a bit of practice makes it snug, but not impossible. Work at it.