It's been my experience that there is about a 50/50 chance that a spike will develop a rack.

On the ranch I hunt on, we hammer the spikes. Roughly half of the spikes I have killed have been over 1 1/2 yrs of age.

A deer with good genetics should have a forked rack for it's first set of antlers.

Will a spike ever grow a rack? Maybe. Will he ever have a "good" rack? Probably not. Will he ever have a "monster" rack? In my experience, never.

Just my 2 cents.