I have tried for years to get some information about this model and, in spite of exhaustive research, I have never been able to find an original vessel of that name and date. TJ's reference is actually for a different ship.
I once contacted Mammoli who originated the kit but they were unable to come up with any prototype information other than what their art department had placed on the box saying simply "Built for the French Navy in 1848, L'Orenoque relied on a combination of sail and steam." I suspect there may not have been a prototype ship.
I have seen a finished example of the kit and it yields a superb display model.
PJ
Vcitoria, British Columbia, Canada