Been mulling over building a railef CCO for some time now. If I have yet to find a officers frame with a rail on it...and I have a spare 80% commanders frame with one. Unfortunately it's 7075 so welding or soldering it is out. My thoughts were to make a filler plate to fill in the grip cut out, then drill & tap for the grip bushing on the new filler plate, and then cut the frame down to officer length.

I question whether epoxy would hold the filler.
The edges of the frame hole are thin and won't give much of a bond with the filler plate.

I'd worry that under recoil the filler might pop out.

One possible way would be to bevel the inner edges of the frame hole and bevel the filler the other way.
That way the grips would pull outward on the filler and wedge it tighter in place.
That along with a good epoxy might work.

For epoxy you'll need a stronger type then the usual 5 minute or even one hour hardware store type.
Here's a very high quality epoxy developed for custom knife makers.
This is TOUGH stuff.  Takes a full 24 hours to fully cure......

http://bladebond.com/

Why not get one of the rail sections that they sell for the 1911 to convert a non-rail to a rail, and just put that on your officers model?  Will the dust cover not be long enough to hold a light?  I'd think you would have to use an X2 or something small like that anyway.

I have one on a Para P14-45 that works great, but it's full size.

Didn't even think of that.  I forgot those add on rails existed .