Paul, congratulations, and enjoy the car. It is my favorite Russkit car too.
However, and to help you with future "picks" and stricly talking as a purist (you do not have to be one!), you should know that your car is not a genuine Iso Grifo RTR, but a car that was put together from unrelated parts, using the Russkit Iso aftermarket body (sold unpainted and with a different decal sheet from the RTR model), the 2-piece Lola T70 chassis (the Iso had a unique one-piece chassis), motors built with endbells of the wrong color (the Russkit "22" and "23" endbells are always made of white plastic, only Cox and Marx' Mabuchi FT16 motors used black endbells), and the wrong wheel inserts (while they match the "spare" wheel molded with the driver's compartment insert, the genuine Russkit car had the same "wire" inserts seen on their injected-body Cooper-Climax, Ferrari 156 F1 cars as well as their two Chaparral models).
There were two types of front wheels, one "standard", te other extra narrow with specific tires.
This of course does not mean that there is anything wrong with your car, in fact, this should allow you to race it as hard as you want, because it would not be too good to risk a crash and body cracks damage to a rather scarce genuine RTR.
I enclose a few pics of a few Iso RTR models, as well as both their packaging forms.