The retract ready version does allow for the installation of the fixed gear, but the process is not really reversable as designed.

In other words what you install is what you'll be flying with...

The attachment block for the fixed gear gets epoxied in the wheel opening that would be used by the retracts.

I'd imagine that you could rig up something, but it would require some machinations...

---

Meanwhile my Bobcat .25 is coming along too...

I hope to post pics and maybe some build tips when I am done.