When the 955's were built it was to homolgate them for the AMA series.
They actually stopped producing the 916sp3's in the middle of the year to build the 955's.After they built the 955's they then started to make the 996 engines.
They were all shipped to america but some were brought back to the uk and the company who brought them back(H.T. Automotive).Got the ones they brought back plaqued.
When they were sold they were sold mainly to race teams in america but some guys bought them and kept them as investments.These are the ones that are now appearing now and again for sale.
I am not sure how many made it back to the uk.
Bear in mind as well that these bikes were built at a time when even the spec of the uk bikes changed on a daily basis depending on what was available at the time.
I have seen sp3's with showa rear shocks instead of ohlins.
I owned one for a very brief time and it kicked out 150bhp when i got it.
It sounded really rough though.The idle was all over the place but once you got going it was mind blowing.Mine had ferraci pipes on it.Not termi's.
If i was going to buy this bike i would get the engine and chassis numbers and call ducati to try and verify if this was a genuine bike.
As with any bike though be wary of it.If you don't feel right about it don't buy.
My only concern with this bike is the fact that the last time i saw one for sale in the uk it was for sale at £25,000.
That is the going rate.
Hope this is of help.