Aye Graeme,
No!
They look very whizz and I suspect if you are travelling at speed along the Manx roads they may have certain advantages when being used as intended by "The Gods!".
Whilst the materials and engineering may be better than the Girling "Gas" shocks of the 1970's, I doubt if they are that much different. I did use a pair of those (ex- Manx ISDT) that I acquired in 1976 when living on the Island. They were 330mm between the eye centres, rather than the standard 310mm and certainly made the front end twitchy going up through Druidale, with the IoM VMCC at a gallop!
For a mortal, I find the Spanish Betor twin shocks quite adequate on the 450 and of reasonable quality, giving a firm, well damped ride for my 85Kg (~13 stones). They are available direct from the factory for E100-00 per pair + Tassie import taxes and duties.
They also build competition "gas" shocks, have a scan through their website.
Betor_Ducati_450_rear_shocks_linkBetor_Road/Race_"Gas"_shocksGood health and a plush ride, with whatever you choose, Bill