If the length is the same as the pitman arm, I doubt it would be any problem. The curve was probably designed to improve clearance. Looking at your pictures, I can see that this isn't a car built to factory specs, so I see no problem with it.
It is in fact slightly shorter, about 1/4." the curve lessens the clearance as it contacts the pan before the outboard part of the idler arm can get full swing. If it were straight, it would have more clearance.
All the suspension is factory "Spec" as far as fit, form, function.
