FBinNY 

if the fork is off center, or more important, the wheel off from the central plane, there would be consistent pulling to the same side. Absent that, It's reasonable to assume that the wheel track is within acceptable tolerances.

High speed wobble is often discussed here. It's a harmonic phenomenon, resulting from a number of factors, and solvable by a number of methods, from changing the harmonics, lowering front tire pressure, changing weight distribution at high speed, and so on.

The fork being off, though not enough to cause pull, may contribute, but equally so, it may not, and changing the fork may not change anything.

In any case, I suspect that it will be hard to warranty a fork for alignment after 5 months is going to be difficult. And fixing the "problem" requires analyzing the specific issue, which may be one dropout slightly higher than the other, or the fork ends being off center with respect to the steering axis.

FWIW - and to give a sense of perspective, if it's a question of dropout height (easily fixed with a round file), there's a multiplier effect, and it takes less than half a millimeter to cause the 4mm TIR you report.

Also, know that if you elect to "fix" the fork, you might actually move it from OK to not OK and cause the very problem you're hoping to avoid.

So, my advice is to leave bad enough alone Or if you can't, to remove the fork and do a series of precise measurements to discern the EXACT errors, then address them specifically and correctly.

BTW - the easiest, though not assured, way to manage high speed wobble is to descent with pedals horizontal and one knee braced against the top tube. This changes the harmonics and dampens and usually totally resolves the wobble.

Another is to relax or tense slightly. Part of the harmonic system is related to how firmly you resist the wobble by bracing the bar. Often relaxing a bit slows and eliminates the wobble, other riding in the drops and bracing harder by pushing both sides forward does the trick. There's no set one size for all fix, but most cases can be cured through trial and error until you dial in the formula.