If you were not highly trained beforehand, then yes, any aerobic gains from cycling will spill over into running. If we are to belive Joe Friel, (and he has a pretty good rep)

taken from Joe's blog posts about specificity: Joe Friel's Blog

"One I deal with a lot has to do with triathletes and bike races… Many multisport athletes believe that bike road racing is good training for triathlon. It’s not. Bike races are, indeed, aerobic events, as are triathlons. But that’s where the similarity ends. The outcomes of bike races are determined by two-minute episodes when all hell breaks loose. They are anything but steady state aerobic. Bike racing has a huge anaerobic component which is critical to success. No one in their right mind races a triathlon that way. Triathlons are steady and anaerobic intensity is avoided. A bike race done by a triathlete is largely a wasted workout day. It’s even worse than that because the recovery after one of these delays when the next, truly specific triathlon workout can be done."

You should check them out, they explain much more than I care to copy in a single post .