yeah, front mounting is fine. as long as the case has room and adequate fan space, then the radiator can be mounted wherever.
front is actually preferred. some people say it should be set up as an exhaust so hot air isnt being brought into the case, but the thing is, then your cpu is being cooled by hot air(from the gpu for example) and temps a greatly effected. whereas the heat off the radiator only increases the ambient temp inside the case by a degree, if that, having no effect on the other components. due to the way radiators work , and the laws of thermal dynamics, the air coming off the radiator isnt hot enough to effectively heat up the interior of the case.